It’s the last weekend of summer and Capitol Hill has much to offer. Here’s a selection of cool stuff to do.

H Street Festival

Washington’s epicenter of quirkiness celebrates its annual street festival on Saturday, and the word is it’s going to be enormous, with some folks estimating more than 100,000 people will come to listen to bands, drink craft beer, buy ridiculous T-shirts, eat street food, eat organic farm food, dance in the street and just plain have a good time. From noon to 7 p.m., from the 400 block to the 1400 block of H Street Northeast.

Worldly Music

Nader Majd, director of the Center for Persian Classical Music in Fairfax, Va., and Chakavak Ensemble perform classic Persian music on Sunday at Hill Center DC. WAMU’s Mary Cliff moderates a discussion with them to start things off. From 3:30 p.m. to 6 p.m. at 921 Pennsylvania Ave. SE in Hill Center’s Abraham Lincoln Hall. $15. To purchase tickets, go here.

I was Told There Would Be No Math

Hill Center DC is showing “Do the Math” on Sunday, a documentary film by Kelly Nyks and Jared P. Scott on climate change that focuses on the efforts of environmentalist Bill McKibben to take on the fossil fuel industry.

https://www.youtube.com/watch?v=-zfinOCgRQ0

It’s a heady topic as the Keystone XL Pipeline debate continues to loom over Congress and the administration. The 50-minute film is followed by a panel discussion with directors and Kate Colarulli of the Sierra Club and Robby Diesu of 350.org, McKibben’s organization. From 7 p.m.-9 p.m. at 921 Pennsylvania Ave. SE. Free. To register, go here.

Last Call for Baseball

The Washington Nationals are not out of it yet, but just in case they fall short of the playoffs this year, make sure to check out their last regular season homestead of the year, with three games at Nationals Park against the Miami Marlins. The Nats beat the Fish in a squeaker Thursday night, 3-2, so they’re on another roll. There are 7:05 games Friday and Saturday nights, and Sunday’s bounce game is at 1:35. The Nats finish up the season by hitting the road for St. Louis and then Phoenix, so this might be the last chance to see them in 2013 if they don’t get a few breaks to make it into the post-season.