Kinda dumb. Kinda ridiculous. Kinda didn't really go anywhere much. But all that said, well worth a watch. James Franco pulls of a truly excellent loveable stoned idiot character, Seth Rogen plays himself (as usual), which would suck if you don't enjoy his schtick, but I do.
It's basically your typical Superbad/Knocked Up/40-Year-Old-Virgin Apatow movie. If you liked those, you'll like this. If you found those to be a little too "clever" for their own good, this isn't for you.