so I've tried out a lot of Amumu builds and now am now sticking with this build which I have customised myself.
taking note:
-boot might change to threats for extra magic resist
-armour might be changed for physical damage or magical damage

this is the the build I use for physical opponents that is why armour is at 317.7 +health at 3900+

some of the games iv had has lead me to god scores as show in the picture below.

I like to change it up a bit depending how I feel but normally I use:

-Heal -To remain in the lane for longer at early game

-Exhaust -To slow and weaken enemy champion so ether you or your partner could go in for the kill

-Ignite -To hurt your enemy while your cry is on...extra damage.

-Ghost -this is ether to run away with or to use to catch up to an enemy with you despair of bandage toss moves to go in for the kill

this all depends if I want to kill or helps a partner in my lane out.

The teamwork for Amumu in a game is crucial as you could be doing very well in your scoring or the game will just freeze up and be pointless but never give up because Amumu is the best champion to turn the whole game around specially when he cannot be kill so easily.

the top score in my picture was the biggest turn around I did during a game as one champion was surrendering about 7 times and I proved him wrong by leading my team to victory.

Amumu is probably one of the best teams fight starters in the game so make sure your not alone when fighting other champions as Amumu cannot handle 1v5 in a match but can lead a 3v5 killing at least 3 of the enemy champions and its also a potential penta killer is you can get the right timing (not done it yet but I'm trying =D).

Right so Farming could be a issue for Amumu and I find I cannot farm fast enough without my despair which wastes my mana or just have other good farming champions kill the minions before you do early game.

This is why I start off with tantrum and max it out as soon as I can so I can farm better and use it for combos against my enemy champions.

unfortunately all other moves that Amumu can do it not for farming which makes it difficult to farm unless you decide to use the curse of the sad mummy move against a load of minions which might be a waste.

you have four moves
-Bandage Toss - this move launches Amumu to its target if successfully hit which stuns the enemy and deals damage

-Despair - this move lets out Amumu's emotions and makes an AoE effect of tears around Amumu which damages enemy's inside the AoE over time.

-Tantrum - this is when Amumu gets all aggressive and hits everything around Amumu.

-Curse Of The Sad Mummy - this move is Amumu's Ultimate move which makes a Massive AoE Ring around Amumu and stuns every enemy inside the ring and deals damage.

HARRAS
basic harras move is the bandage toss and then tantrum. you can increase this damage by activating you despair as well, but its a harras so after that combo you run and get distance until you enemy is low enough to kill.

Team Fight Attack
This is a very similar move but it require you using all four of Amumu's abilities
so when you see a team fight happening, Despair then Bandage Toss into the group of enemy's and then Curse of the sad mummy which will stun and allow your team to come in for the kill unless you have done so already, this ganking move is the key to turning the game around to be victorious.

Fair warning Amumu has not got a lot of mana so watch out when jumping in and not being able to pull off the tantrum move straight after you hit them with bandage toss...
- bandage toss + tantrum = 140 mana

the first thing you should do is get a good team together and a happy bunch too so it will be a laugh even if your losing, Amumu can pull off some funny moments like throwing his bandage through walls and killing people as well as risking a turret jump for a kill which makes the game have a better feel to it =D

start crying with Amumu despair and and chase champions down to there turret and make the enemy team scared to be near you, even running into a group you could scare all 5 of the enemy team. (I have =D)

and for kicks shout out to the enemy team 'Don't Worry guys AMUMU is COMING!!!' or just the casual 'WaHHHhHhHhHhHh' just to see there reaction =D
Another one which I love shouting out is 'I just wanted a hug..wahhhhhhh' lol its brilliant, some of the response's from the enemy is really funny.
play with Amumu and enjoy it =D

so basically this build will help you get a few kills (or a lot of kills) and help you stay alive.
doing some skill shots will keep you entertained while you fight your way to victory and so other people that you got skill.

-this build takes patients and a lot of money =D

-if you can achieve champion kills early game you money will be rising fast meaning your build to a unstoppable Amumu will be very close to you.

-Amumu is a lonely mummy but with a good partner in lane you will be happy I assure you because Amumu has a good was to become a Carrie as well and helping your partner become a carry which as shown in my picture I had 29 assists :P

I personally love this build and I love using Amumu so join this Sam mummy and show other people how much Amumu rocks in the league of legends game =D

so any improvements you would like to add please do, just leave a comment and I hope you enjoy this build.