Crankarm falling off mid ride?

Did it break or just "spin" off?

There's no way to not make this sound snarky so I'll just say it...

It has never happened to me because I really pay attention to my bike's maintenance.

Yep  Two pinch bolts.  Just came loose?

Not snarky at all.  Understood.  I didn't realize that could happen to just "spin off"

It happened to a female pro, i forget her name or the race, maybe LP? and she was given a bike by another (smaller) rider and was DQ'd for making forward progress without her bike.

But she snapped hers.

Didn't snap mine.  Looks more like it just spun off.  Going to head to the bike store this morning to get it checked out.  Went last night with front de-railer issues. 

I had that happen during a race.  And it sucks.  Basically it's simply a manner of checking your bolts on a routine basis. 

I was doing a HIM Relay so I used my road bike with shorties and didn't properly check it beforehand.  So long story short, always check the major bolts on your bike at least once per month.

Think its simple enough for me to fix?

Had it happen in a group ride at about 25 mph.  Riding along and all of a sudden the left crank arm and pedal are just swinging from my cleat.  I was new to cycling, had no idea what had just happened so I kept pedaling to avoid causing a pile up and the next thing I know, the entire right side assembly is hanging from my right cleat.  

Three things I learned from that experience:

1. Routine bike maintenance is a must

2. Stop pedaling when something breaks or you'll make it worse

3. It's really hard to unclip when your crank is in 2 pieces 

Yes, it's just a matter of putting it back on and making sure the torque is correct.  But I would at least have a bike shop look at it just in case.  Plus you might need new grease assuming it's not still back in now.

Yes very scary, I had it happen to me on the road with my FSA crank.  Had the retaining bolt for the crank assembly come out on me in the middle of a training ride.  There I sat wobbling along with a pedal attached to my left foot and a pedal/crank assembly attached to my right foot....in aero.

Some hairy scary moments for a bit but I manage to keep the bike rubber side down and come to a stop.  Had to call the wife after a search for the retaining bolt was fruitless.  Went and got another one, couple of dabs of locktite on the threads and now I'm good as new.

Heather Wurtele at Coeur d'Alene

It was my own fault, I replaced the BB 2 weeks earlier and failed to reinstall the left crank with enough torque so wobble wobble wobble, off it came.  I was not carrying a 8MM allen wrench either (now I do).  Lesson learned.

So what to do in the middle of the race? I one leg pedaled for the rest of the course, which sucked for 8 miles of hills, but I did not DNF, in fact had a PR at this race and my fastest 10k run split ever.  I even got the race photo of me with the crank arm in one hand at mile 20 with a huge smile on my face !

Where does one find torque values for bikes? Would an LBS have the specs? 

Also, remember that lubricating a thread (for example, with loctite) will lower the torque value needed. Adding the loctite and torquing to the manufacturer's recommendations means you're overtorquing. Just one more thing....

Had this happen on the commute into work 2 summers ago (Trek 7.3 fx hybrid)

Flat ground, no issues, pulled into a ATV place, and got it back on well enough until I brought it back to the LBS where they replaced the crank.

We've had that happen once at the shop in the three years I've been there.  One of the guys didn't torque the bolts properly when they installed the crank.  Those bolts are meant to be at 13-15nm, which is significantly tighter than the "snug" that a lot of people will do. 

Although I would imagine you've resolved the problem by now, make sure that the splines on the inside of the crank arm are still in good shape, sometimes they will be damaged as the crank arm wobbles off.  And luckily it happened indoors so you didn't lose the compression plug.

I did get it resloved.  Thanks for all of the comments guys.  I did end up finding the compression plug on the floor.  Definately will look into this a lot more.

Definately need to take a bike mechanics 101 class to get confortable with these seemly simple but semi advanced fixes.

Had one start coming loose, but re-tightened and that fixed it.

Did you have any sounds coming from it first?