Yea Jetblue is the number one choice for flying out of Richmond. Sucks if you didn't have tickets because they just ended a sale for $64 one ways from RIC to FLL . . . $150 RT after taxes I was getting (I do travel) and that includes a carryon and one bag under the plane. Delta has some $180 RT deals for those dates as well.
As far as things things to do . . . really depends on your age. If you are young and want to hit the clubs, personally I would hit South Beach on Friday Night and then hit the Hard Rock on Saturday night. Enjoy the Beach on Sunday. You probably understand you should get a car rental if you "really" wanna do some sightseeing. The Miami/Metro Zoo is still decent but skip the Seaquarium . . . it sucks, especially for the price. If your are based out of Fort Lauderdale, give Las Olas or Beach Place a try. Key Largo is nice, if you wanted you could also take a day trip down to Key West or even spend a night down there. Plenty of snorkeling and jet skiiing to be done, but you aren't that far from Va Beach being in Richmond, so you can do that when you want if you really wanted to do it.
Shopping I would suggest Aventura or the Sawgrass . . . of course if you got it, you can blow a wad on South Beach on Lincoln Road. Sawgrass Mills is the largest Outlet Mall in the country . . . usually has something for everybody out there. Aventura I believe is the 4th largest mall in the country.
Everglades is nice. They have some real solid tours out there. If it is hot as it is right now, you may wanna skip though. The heat, humidity and swamp is a bad combo IMO . . . but it can be fun. Consider a day cruise as well out of Miami.
Most people wanna have Cuban food. You can hit 8th Street . . . Versailles is real popular outside of Calle Ocho. Joe's Stone Crabs is popular on SOBE.
Alot of stuff to do, just depends on what you wanna do.