Check out this fun update on what athletes are doing around the world for next Saturday from our friends at Outside Magazine. And if you haven’t seen it already, make sure to visit our 350.org/athletes page to see all of the great athletes that have lent their support (and sweat) to this growing movement.

This Saturday, October 24th, will be action-packed. Normally, this would not be news for Outside readers, for whom most weekends are packed with biking, skiing, boating, etc. But this year, it’s news. October 24th is the much-anticipated international day of action, designed to get everyone—really, everyone—talking about climate change and demanding action from world leaders to make real strides in mitigating its impact by signing a new, aggressive treaty during the upcoming United National Climate Change Conference in Copenhagen.

Hard to say whether this Saturday’s actions will set off the chain re-action we imagined in the October issue  (well, OK, that scenario is a real stretch). But you’re probably going to be out and about this weekend anyway, right? So if you believe climate change is happening, if you believe it is a real threat to humanity (not to mention your outdoor recreation opportunities), and if you can count to 350*, there’s really no reason not to add your voice—and sweat—to the choir.

Here’s a small sampling of the more than 4,000 events that are planned, or already in motion, around the world (170 countries and counting):

A dozen Bay Area cyclists took off Monday on a 350-mile ride down the California coast. They’ll arrive in San Francisco on Saturday. If you’re in that ‘hood, join them for the very last bit of their giro (details here).

Legendary climber Lynn Hill plans to unfurl a 350.org banner (from the top of an still-undisclosed ascent)

Pro XC skiers on Team Steinbock will warm up their legs in a rollerski race for 350.org at Soldier in Midway, UT.

Pro mountain biker Lea Davison is leading a ride in Jericho, VT and Kiwi mountain bike pro Kashi Leuchs is leading a ride in Dunedin, NZ.

Record-setting ocean rower Roz Savage will speaking at a 350.org event in London

Canadian World Cup skiers Thomas Grandi & Sara Renner are leading a ride in Canmore, Alberta.

In Portland, Ore., a gaggle of boaters will form a huge 350 in the Willamette River

Speaking of oceans, in NYC cyclists are planning a "Future Sea Level Ride,"  complete with aquatic costumes, to drive—er, ride—the point home that climate change means rising oceans.

Over in Middlebury, VT (ground zero for the 350.org, since organizer Bill McKibben is a scholar-in-residence at Middlebury College) you can join in on 350 sun salutations, among many other events

And should you find yourself in Times Square on Saturday, you can watch highlights of these global actions as they’re beamed to a 30-foot screen.

So what are you planning? Let us know. And if you can’t join any of the above, find an action on this handy map, or create your own.

*According to NASA scientist James Hansen, 350 parts per million is the safe upper limit for atmospheric CO2. Many leading scientists concur with this estimation. Right now, we’re at about 387 ppm. So we’ve got some serious back-pedaling to do.

Mary Catherine O’Connor is a freelance writer, covering the environment, sustainability and outdoor recreation. The Good Route, her new blog for Outside Online, is focused on the places where the active life and sustainability merge.