I have one for you, I have played on a 28.8.
Delta Force: Black Hawk Down FPS
WoW, can get laggy sometimes when around a bunch of people
Played Everquest for 7 years on a 28.8
Guildwars was playable
CoH-NOT PLAYABLE
World War 2 Online worked on my 28.8 and I know many who play on a 56k and don't experience lag