Just got directed to this site from Marcelo Garcia which features a slew of searchable videos.
One of the first videos I watched had to with an arm bar known in jujutsu (jiu-jitsu, whatever) circles as the "omoplata" (it looks like embedding his videos on a blog is allowed, but you can follow the link). In the judo world, however, it would most likely be refferred to as sometimes referred to as ude-garami or sankaku-garami ("triangular entanglement") or ashi-garami ("leg entanglement").
For whatever reason, it's not one that I've ever spent time on, and never knew existed until I started investigating BJJ a little. Frankly, I'm intrigued. I've seen a few odd ball entrances to it, which at first made me wrinkle my nose (a little too complex for my taste), but I've since seen a few that looked a little more palatable, such as this entry from Derek Hall at our humble li'l dojo:
I'm looking forward to playing with it—but for now, it's "sankaku jime/garami" month! So far, I'm having fun focusing on one basic principle and all its various applications and entries and so on. Maybe next month will be "ude garami" month....