I've just recently signed up to Estiah which is a "Magic the Gathering" type of deal where you design your card deck based around your combat strategy and play off against computer or player controlled opponents with similar decks.
This has a bit of a MMORPG/levelling element to it however, and because of the way the game is designed (you get a certain amount of action points every 2 hour session which you can spend or store to do several small sessions, or do one large playthough) makes it perfect to catch up with during your lunch break.
The game is very basic, no real graphics to talk about, its mainly text based, but theres some quite humerous descriptions of things as they happen.
Its entirely free to play, so if anyone is interested in it, feel free to give it a go as well, ideally using my friends code which subsequently helps me level up a bit faster by giving me a portion of XP whenever the people I invite level up themselves.
It might not be the best idea to ask me too many questions about how it all works at the moment, im still learning myself, only been playing with it an hour and used up my initial full day worth of action points really quickly, but the tutorials and FAQ/Wiki seem to give a good bit of insight.
Anyway, if anyone is interested, please feel free to join up using my friends link