2D MOBA game Awesomenauts is now available to try free of charge on Steam, courtesy of another free weekend; you have until Sunday 1PM PST until you have to pony up some dough to play more ($5 while it's on sale for a bit now, and $10 when it's not).
Besides calling it MOBA (which gets progressively more fun the more you say it -- MOBA, MOBA, MOBA MOBA MOBA...see?), Awesomenauts is also described as a 3v3 action-heavy platformer -- certainly not something you see every day. If only for that (and the rad art design), I'd say give it a download and see what the fuss is about.
Hit the source to grab it now while you can.