5 things to do under $5

1Freakonomics author talk: You've got to give big props to any writer who can make economics sexy. You can hear how at a talk today by Stephen J. Dubner, journalist and co-author of Freakonomics, a book about cheating teachers, bizarre baby names, self-dealing Realtors and crack-selling mama's boys. He and economist Steven D. Levitt say conventional wisdom is often just plain wrong, and they set about gleefully ripping apart our conventions, like why parents really don't matter as much as we think, using the theory that economics is, at its root, the study of incentives. Dubner's lecture is at 6:30 p.m. at the Tampa Theatre, 711 N Franklin St. in downtown Tampa, and is followed by a book signing. Free.

2$5 Day at the Zoo: Load up the kids and get to the Lowry Park Zoo early, because this deal only comes along a couple times a year and it's hugely popular. The crowds are often three times their usual size because everyone gets in for $5 — instead of the usual $23.95 adult admission — on Sunday starting at 9:30 a.m. You still have to buy tickets for some rides and experiences, like feeding a giraffe or riding a camel, that range from $1 to $5 each. The zoo is at 1101 W Sligh Ave., Tampa. (813) 935-8552.

3Amtrak Exhibit Train: In celebration of the 40th anniversary of Amtrak, the public is invited to tour the traveling exhibit train displaying memorabilia such as vintage advertising, menus, dinnerware and period uniforms, plus a train-themed kids area. It's free from 10 a.m. to 4 p.m. Saturday and Sunday at Union Station, 601 N Nebraska Ave., Tampa. (813) 221-7601.

4Old Man Appreciation Bowl Jam: The dudes at Skatepark of Tampa are respecting their elders Tuesday — meaning those 25 and older — with free pizza and skating, and a special bowl jam starting at 5 p.m. We know how those 20-something seniors like their early-bird specials! At Skatepark of Tampa, 4215 E Columbus Drive.

5CoMotion and Friends Dance Concert: St. Petersburg College CoMotion Dance Theatre combines with Hillsborough Community College Dance Program for a night of modern dance choreography. Guest choreographers from around the Tampa Bay area bring innovative moves to the stage. It's $5 admission at the door at 8 p.m. Friday, free for SPC students and staff. Palladium Theater, 253 Fifth Ave. N, St. Petersburg.

Sharon Kennedy Wynne, Times staff writer