Field-trip buses tend to deposit swarms of grade-schoolers at this historical site nearly every day of the year, so plan your visit to the La Brea Tar Pits with a bit of flexibility.  The smell of the outdoor pits is a heady mix of gasoline and something richer and more primal, and the oily mini-ponds look like brown, bubbling sludge.  Why are the La Brea Tar Pits famous?  They trapped the remains of fossilized dinosaurs, saber-tooth tigers, insects, plants and woolly mammoths from the Ice Age, preserving them and presenting a picture of Los Angeles’ past for today’s scientists.  The La Brea Tar Pits themselves are free to observe, given that they’re outside, but to enter the Page Museum or the Los Angeles County Museum (LACMA) exhibits, bird sanctuary and gift shop, you’ll have to pony up between $5 and $7 each. The park surrounding the tar pits is open to the public, and it’s a great place for a stroll.  Families congregate on the weekends, and the occasional musician will hang out and play.  Statues, craft fairs and joggers are a familiar sight.  It’s a fun, casual place to get your learn on.