My university switched to something called Canvas (right after I graduated, of course) and it's incredibly slick, on top of it being fully OSS. Sakai is out there too — the quality isn't much better than Blackboard but at least it's free!
Sakai and Canvas seem easy enough to setup that I can't imagine Blackboard can continue making money for much longer.
There's another system called LON-CAPA (written in Perl) that seems ancient compared the other competing systems. It was very easy to use and "just worked" but it felt like it was straight out of the Web 1.0 era.