Medialab, yes, but it requires you to run it through VirtualPC. DirectRT, no. Some labs run MediaLab on Macs via Microsoft's VirtualPC. This program allows the Mac to pretend that it's a PC--just a bit slower. We don't support it but it can be done and from what we hear, MediaLab runs pretty well on it, looking and feeling much as it does on an actual PC. A G4 or G5 processor with lots of memory would be a good idea. I have run it myself on a G4 powerbook and thought it was pretty cool. In contrast, DirectRT will not run through Virtual PC on a Mac because of its dependence on actual (rather than simulated) PC hardware.

Now that Macs are about to utilize Intel chips though, the world of Macs may be opening up to us in a much bigger way. We'll see.