People like cooperative games and that is also fun on android phones and tablets. Tjeck out the list off coop games for Android phones and tablets.
UPDATED: feb 2012
Among the Undead (new may 2011)
Raging Thunder (online vs multiplayer)
Raging Thunder 2 (online vs multiplayer)
If you know other coop games for android please write it here.
Some more coop games for Android
Pool break Pro
More coop games