Swimming Under Clouds by Yacine Salmi and Orioto (preview)

Tale of Tales had compiled a list of videos submitted by entrants for the IGF 2010 competition which you can watch here and here. Lewie Procter of SavyGamer is also in the process of compiling links to IGF entries with playable builds online to download or play, although you might have to wait a bit for the rest of the alphabetical links to appear on his site.

More notable videos (IGF and non-IGF) can be watched in the extended.

development video for Revenge of the Titans, by Puppygames (due Christmas '09)

Frobots by Fugazo, Inc. (playable demo available)

Algodoo (previously called Phun)

ASCIIpOrtal introduction (playable build available)

Puzzle Bots demonstration

pitch for Muzikaze, by Pow Studios

trailer for Zero Gear, by NimbleBit

trailer for Ciro, by SpinVector

trailer for the Time Pilot-inspired Nanovoid, by Lazycow

teaser for Driftmoon, by Ville Mönkkönen (of the highly-rated Notrium)