Well this probably won't be one for the "In The Loop" fans who panned my review of that movie, but if you're looking for a bawdy Carry On/Scary Movie style homage to the caveman genre this will be up your street. Not that the plot matters much in this sort of film but it does kind of spoof 10,000 Years BC. Unlike that movie the only cringing you will be doing is from some of the more squirmish humour.
As others have commented, this is really for adults only and would not recommend viewing by under 15's.
Jack Black is back on form as I didn't enjoy Be "Kind Rewind" at all.
Embarassing moment for me...I actually thought at first Michael Cera's character was a girl!
There's all sorts of cameo appearances, the highlight probably being Vinnie Jones as a sadistic soldier. Be sure to stay for the gag reels during the closing credits.
This is not a movie which is going to win any awards but it made me smile and at around 90 minutes is perfect for a bit of silliness to unwind from a busy day.