Experience the OpenAir Circus. In Cambridge and Somerville, you don’t have to run away to join the circus – you can stay here and do it. The OpenAir Circus, a nonprofit, community-based program, is ready for its annual showing off of skills its students learned during summer classes. This 28th annual show, in which “OpenAir Circus Plays with Magic,” features more than 200 children and adult performers and takes place at 2 and 7 p.m. Saturday and 2 p.m. Sunday at Somerville’s Conway Park for a suggested donation of $3. The show is about two hours long with one 15-minute intermission, and refreshments, souvenirs and circus equipment will be available.

Sing Gilbert and Sullivan’s “Mikado,” just because. MIT’s Gilbert and Sullivan Players are holding a free open sing-through of “The Mikado,” the beloved 1885 comic operetta, for anyone who happens to want to proclaim themselves “three little maids from school are we” or “gentlemen of Japan” or perhaps even a Lord High Executioner – no audition or experience as maids, gentlemen, executioners or singers necessary. (Also, there are snacks.)

“Full of colorful music and characters, unexpected plot twists and death-defying leaps of logic, ‘The Mikado’ has been one of Gilbert and Sullivan’s most popular operettas,” organizers say. “Whether you’re a lifelong Gilbert and Sullivan fan or this is the first time you’ve heard of them, the MIT Gilbert and Sullivan players welcome you to a fun, friendly community drawn together by Gilbert’s witty lyrics and Sullivan’s catchy tunes.”

The sing takes place from 4 to 6 p.m. at the Massachusetts Institute of Technology’s Building W20-407 at 84 Massachusetts Ave.

http://www.youtube.com/watch?v=CDR-z7YkB60

Say “Aww” for seven solid hours at Pet Palooza. Yes, you can make fun of an event calling itself “the world’s premiere canine aquatics competition” because, really, are there many rivals for the title? But when that “DockDogs” competition is part of Pet Palooza, two full days of pets and play that features local nonprofit animal organizations and rescue groups alongside dog-training exhibitions, children’s activities and food trucks, it’s hard to snicker. Especially when you can vote for a favorite not-for-profit animal organization and get $1 donated to their cause by Pet Palooza – with up to $8,000 to be donated. (Click here to vote via Facebook, but you have to “like” the event first.)

Oh, wait. Then DockDogs says it has dogs jumping and flying into a 30,000-gallon pool “like nothing you’ve ever seen before.” And it’s a little funny again. Watch the crazy, hyper-intense video above – in which dogs jumping into water is presented like a high-stakes extreme sports event produced by Jerry Bruckheimer – and you might miss all the cute dogs because you can’t stop your eyes from rolling. Still: cute dogs.

This free event runs from 10 a.m. to 5 p.m. Saturday and Sunday at Assembly Row, Grand Union Boulevard, Somerville.

Feel alive with some restless, wandering undead rock bands. Okay, there’s almost a theme here, if you take in that Cambridge’s Spirit Kid, which embodies the short, beautiful pop craft of the ’60s, will be playing a bill with Beware the Dangers of a Ghost Scorpion!, a Somerville band that plays horror-surf rock. The odd band out is pow wow!, a New York/New Jersey quartet with a shoegaze bent. (An argument could be made that drummer Sal Garro represents the ghost of long-deceased local band Pinocchio Syndrome, although more recently he’s been with Brooklyn’s Quiet Loudly.)

The three bands play for $8 at 9 p.m. at Great Scott, 1222 Commonwealth Ave., Allston, in a 21-plus show. There will also be DJ sets by everydayisamixtape.

http://www.youtube.com/watch?v=P8yf3QW1SGg

End the weekend with some hard, guitar-strummed truths. Joe Steinhardt can’t be accused of rushing to market for a buck. He’s been writing – and throwing away and rewriting – the songs on his Modern Hut album, “Generic Treasure,” for six years. Now he’s ready to let you know what’s he’s been thinking, and it’s not for everyone. Although his caustic observations delivered via electric guitar are leavened with production and playing by Screaming Females’ Marissa Paternoster (who also performs as Noun before Modern Hut goes on), Steinhardt is intent on being a little dissonant – like a less playful Daniel Johnston performing in a mumblecore musical. Rounding out the bill is Dessert First, featuring Lily of the Boston anarcho-pop band Parasol.

The bands play 9 p.m. Sunday at Lilypad, 353 Cambridge St., Inman Square, for a $5-10 sliding scale admission price.