Recently the ClanLib team released version 0.8.0 upon the indie game development world. This "game SDK" boasts an impressive number of games built using it, and one of the more notable ones is Pingus.
Another cool ClanLib-based game is Peng2illa. This circular pong-on-rails game is very good looking and about as fun as pong can be.
Sadly many of the games in the ClanLib list are either obselete or their development has stalled. Feuerkraft is one such example of any exciting game whose author, the prolific grumbel, has not had time for in the last few years which is a shame because it looks like it could be so cool if it was developed a bit more.