With Hubway season almost over, you may not get much use out of this, but file it away for the spring: Chris Snyder recently discovered a trick for getting a Hubway bicycle that's stuck in its docking bay.
Sometimes, Hubway bikes refuse to be undocked. The gears on the dock whir for a bit, and then it flashes a red light of failure (not to be confused with an always-on red light that signifies the bike needs to be repaired). But the bike's merely stuck, probably from being improperly docked the last go-around.
When this happens, the trick is to push the bike into the dock as hard as you can, as if you're trying to dock it. The dock should let the bike out if you do this. I've had success each of the three or four times I have tried this technique thus far.
I know that sharing this tip means I'll have even slimmer chances of getting a bike from Kendall Square after 5:15pm, but that's okay, because Hubway apparently just added another docking station by the Kendall T, thank goodness.