Hot Tub Time Machine
This is the true story of a bunch of buddies who get into a hot tub that turns out to be a time machine. Luckily a very skilled camera crew realizes what is happening and dives head first into the hot tub with their HD cameras and catch up with our playful group of foul-mouthed friends in the early 80's when things were really bumping.
Some of the "buddies" go about trying to change their past so that their future will be more awesome. This is a rare opportunity that a lot of people don't get, but a couple of these guys squander their chance and just go about having sex with girls and looking for pleasure instead of buying the domain name, "google," or warning the citizens about the dangers of fiat currency, the federal reserve, and artificially low interest rates that create a false sense of wealth and lead to speculative investing in normally sound assets such as housing, creating an inevitable collapse of the financial system as markets try to correct themselves from mal-investment.
These guys are pretty funny and clever, but unfortunately, due to the stresses of time travel, they resort to vulgar gross out humor to make each other laugh instead of the clever wit you would hope for out of a group of old pals.