Wedding Daze (2006)

Jason Biggs, still getting over the sudden death of his girlfriend, inexplicably proposes marriage to a winsome waitress; when she even more inexplicably accepts, the frolics begin.

You know you're in modern romantic comedy territory when you use the word 'inexplicably' twice in a one-sentence synopsis, but accept that as a convention rather than a fault and you should have fun enough with this basically jolly contribution to the family. It handles its contrived premise with confidence, and carefully balances its appeals to female and male audiences.
The central story is cute enough, and the two leads well cast (Isla Fisher is fully as appealing as she was in Confessions of a Shopaholic); where it slips up a little, as so often with this sort of film, is in the arbitrary and frequently silly characterisation of the supporting characters, and the subplots devised for them. (Edward Herrmann is especially ill-used.) And what's with that naff title?