jQuery Thickbox has been around for a while and we've used it in a bunch of projects and every time I decide I want to open a thickbox programmatically, instead of via the usual binding method, I have to fish for how to do it. The last time I went fishing, I found this and decided to post about it, thinking, "hey, if I post about it, I might actually remember where to find it next time I go fishing". OK, yeah, I'll probably still have to google for it, but anyway, here's the link:

http://blog.gridworlds.com/js/working-with-thickbox

Look down the page for "Calling Thickbox via JavaScript". Bingo.