I had my shoe stuck in a pedal on my bike once when (unbeknownst to me) I lost a bolt on the cleat and the other was loose. Had a bear of a time trying to get them disconnected, and it was a freaky-scary ride home, because it was on my left shoe - the foot I normally disengage at stop signs, etc.
Lesson learned: ALWAYS check your cleats and make sure they are tight!
2007 Seven ID8 - Bontrager InForm
2003 Klein Palomino - Terry Firefly (?)
2010 Seven Cafe Racer - Bontrager InForm
2008 Cervelo P2C - Adamo Prologue Saddle