Two NVIDIA videos: http://downloads.guru3d.com/download.php?det=1357 (be sure to click on both mirrors)
EDIT1: Article about all the HW physics options: http://www.pcper.com/article.php?aid=228
NVIDIA videos
Bricks Demo: http://www.fileshack.com/file.x?fid=8574
Dino Demo: http://www.fileshack.com/file.x?fid=8576
Vortex Demo: http://www.fileshack.com/file.x?fid=8575
ATI video
Physics Demo: http://www.fileshack.com/file.x?fid=8573
EDIT2: More NVIDIA/Havok FX videos...
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham1.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham2.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham3.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham4.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham5.zip
From: http://www.watch.impress.co.jp/game/docs/20060326/gdc_ha.htm
EDIT1: Article about all the HW physics options: http://www.pcper.com/article.php?aid=228
NVIDIA videos
Bricks Demo: http://www.fileshack.com/file.x?fid=8574
Dino Demo: http://www.fileshack.com/file.x?fid=8576
Vortex Demo: http://www.fileshack.com/file.x?fid=8575
ATI video
Physics Demo: http://www.fileshack.com/file.x?fid=8573
EDIT2: More NVIDIA/Havok FX videos...
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham1.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham2.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham3.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham4.zip
http://www.watch.impress.co.jp/game/docs/20060326/gdc_ham5.zip
From: http://www.watch.impress.co.jp/game/docs/20060326/gdc_ha.htm