Haha, yeah, DXM is awesome. If you haven't read it, read the DXM FAQ. (found all over the place). I drank a whole bottle of robo once, in a short period, but didn't get all that high. I did get some effects, but mostly the dissociative effects, rather than any of the other cool crap, like CEVs and visual distortion and crap. I was kinda disappointed... But it was still fun.
That reminds me, I need to try that again sometime.