Nikos Chantziaras has updated FrobTADS, his text-only TADS 2 and 3 interpreter for Unix. The new release brings it up to date with the latest version of TADS and fixes a few bugs.
Cugel is a unified Mac OS X interpreter written by Tor Andersson. It playes ADRIFT, AdvSys, AGT, Alan, Glulx, Hugo, Level9, Magnetic, TADS 2 and 3, and all Z-code versions except 6. It won't yet do HTML TADS, which makes me sad, but it seems petty of me to complain about that given everything it does play. It's alpha software, so expect some flakiness.