Discussion: Just mail it back to garmin...

Just mail it back to garmin, they'll probably replace it. Ken's been through a few I think.

Chuck it and go back to an ordinary Casio that records a couple of splits. Real men don't need need Garmins. What next, after all? Mink stoles? Fru-fru tutus? Mice that don't even get horny?

Get a metronome and count beats at 60 bpm to record splits. Real men don't need devices that store the number of seconds between events. Once you develop proficiency remembering 20+ splits, think how easy memory-O will be.

http://www8.garmin.com/support/outofwarranty.html

after the 1yr warranty, it looks like $79 for 305 replacement. You send them your broken one, they send you a factory refurb. The turnaround is quick since you get a different one back. Some people say they've gotten free replacements after the warranty period, you might have some luck if you call them up.

I can loan you one if you don't get fixed before the TT.

also, before you do any of that, a soft-reset (hold mode + lap/reset) can sometimes fix problems like this, if it is not an internal battery-contact problem.

oh no! this is the end of ross logging training, if he can't dump 25 workouts all at once!

I´ve had regularly occuring problems with my FR305 - about once or twice a year, so it´s not extremely bad, but still annoying of course. It seems to be charging when in the cradle and also says "Battery charged". When I turn it on it dies within a couple of seconds.

This has been solved through charging the watch using the regular "wall charger" and not the USB/computer one. Sometimes the watch looks like it is totally dead and doesn´t even show that it is charging for a couple of hours, but is OK after a whole night of charging.

Probably after trying the soft-reset approach that ken suggests, the smart thing to do is send it off for the $79 factory substitution. But if you want to try a repair, you can find instructions about how to try almost anything on the internet! http://www.jimandkatrin.com/CodeBlog/post/Forerunn...
If you decide to try going that route, you might want to enlist a little help from Ed or one of your other technologically more experienced friends!

I would definitely also try wall-charging it like bubo says.

Also, make sure there is no gunk on the contact points.

It is usually the battery contact issue inside the watch. It's been common issue with FR305 and they are aware and even doing free after warranty replacements. Mine started shutting down after a run once in couple months then more often and finally multiple times during a run. Call Garmin, you might get away with a free replacement even though it's out of warranty.
Even for $79 it's worth it. They send you back a watch with a new case. (not sure if inside they fix or replace it).