I'm thinking of starting the P90x program. I'm a retired male age 65 and am fairly active. I ride a bike 4-5 times a wk, (2 hrs. per ride).

Any tips or comments from "older" people who are doing or have done P90X?

Any tips? Yes.

Let's get this party started!

Seriously, it sounds as if you are very active, however, you may want to consider getting the "okay" from your doctor.

You will be thrilled with your decision to do this program.

Good luck and please let keep us up to date.

I was just thinking about this last night. How old is too old? I'm not sure there's really an answer to that. It all depends on how you've aged. Some 65 year olds have one foot in the grave already. Then there's someone like my grandmother who, at 88, still does headstands when she does yoga. No joke.
P90X is extreme and I imagine that as you get older listening to your body and not letting your ego get in the way become more and more important. Even at 37 I notice that I'm more injury-prone now then 10 years ago. Recovery takes longer too. I don't think that gets any better as you age further. So, you have to be smart to compensate.
My advice:
1. Definitely check with your Dr. before starting.
2. Definitely take the fit test before starting.
3. Definitely do a warm up week before starting for real. I.E. Do everything in Week 1 as it's laid out but only go at 3/4 throttle. Do everything but hold back a bit. Gives you a chance to learn some of the moves as well as assess where you're at and give you an idea of what to expect of yourself going forward.
4. Definitely check in here regularly. It's a great resource.
5. Bring it!