Can you lager a beer too long?

Are there any ill effects on your beer from lagering for too long of a period?

If so, what time scale are we dealing with being too much? Days, weeks, months, years?

Also... if I'm aiming to serve a particular beer at an event, am I better off lagering it until about 2-3 weeks beforehand, then bottling/carbonating, or should I lager it for some set period, bottle, carbonate and let them age in the bottles for the remaining time?

Basically, I'm going to a birthday party in late March, and my beer's pretty much done lagering now according to the days / degree Plato calculations in Noonan's book, so I was wondering if I was better off bottling it now, or leaving it in the carboy in the fridge until closer to the party.

Months, ok; years, probably not.

I believe in bulk aging. On the other hand, I keg, so same-o. By bottling about a month ahead, you can verify carbonation and Total Quality(r).

I made a Octoberfest-Ale type beer in mid August and I wanted to save it until my kegs came online. That was at the start of the year. I lagered it in-between and it turned out awesome. As long as your beer isn't a super low alcohol brew and you don't exceed 6 months I think the beer will continue to improve. If its a big beer you can go longer, if it's around 3.5-4.2 I would let it age less.

Marzens are traditionally lagered for 7 months, i.e. brewed in March to be served in October. Lagering for 6-12 months should not be an issue.