if you mean network gaming then CounterStrike and Quake are the best online games

Hey there is another project by neowebarts on Game search, It has an index of over 500,000 games. Almost all the flash games published on the web are indexed. Try using it

www.games-for-all.co.in

Or else you can go for Armor games, games sheep, 2d play, miniclip etc. You can just run a search in games-for-all.co.in or google will do

Robot creation is a good online game.