One of my favorite computer games of all time (which isn't saying much; I've played relatively few of the many games released in my lifetime) was Lemmings. I played it many years ago on my PC, I played it fairly recently on my Sony Clíe (from ardiri.com), and I played it again today in Internet Explorer. If the Libronix DLS isn't a testament to the amazing things that can be done in DHTML, this site certainly is. (Don't bother trying it in a non-IE browser; it hung Firebird... And please don't kill the rest of your work day playing it... Also keep in mind that he may not have the legal rights to the levels...)

Update: The game can now be found here. This one works with Mozilla-based browsers!