Over 130 games have already been announced and Amazon has a store page for all the FireTV compatible games (nested under their Android category):
http://www.amazon.com/b/ref=mas_lftnav_KFTV?ie=UTF8&node=7031433011&pf_rd_ m=ATVPDKIKX0DER&pf_rd_s=merchandised-search-leftnav&pf_rd_r=1BJ72TARYFEXK530WJ1J&pf_rd_t=101&p f_rd_p=1769971102&pf_rd_i=2350149011
The game everyone is talking about is Sev Zero:
Amazon.com: Sev Zero: Appstore for Android
Amazon purchased this studio who has made some REALLY big games for Microsoft in the past. I'm hoping this game is awesome.