I'm having a problem in my house with CFL bulbs staying on. I have a two bulb ceiling light in the bedroom and a three bulb light in the bathroom. In the bedroom, one of the bulbs goes out after being on for about one minute. In the bathroom, one or two bulbs would go out in about a minute also. If I put conventional bulbs in they stay lit.
I have found a vast difference in the quality of CFL lamps. It is possible you have a batch of bad bulbs. Some brands last for years, other several months. I would swap the bulbs so that one room has all bulbs that don't go out. Turn on the light and see if the problem persists. If the lights stay on replace the defective lamps.
First try switching a CFL bulb that's intermittent with one that works in the same fixture. If the intermittent one is intermittent in this socket too, then take it back for replacement. If it works fine in this socket, but the one that worked fine before is now intermittent, then there is something about that particular socket that is causing the problem. I would then turn off the light and pry/pull outward the base bulb contact. Sometimes they get compressed so much that they don't make good contact. I'd also inspect it for blackness. If its black, I would sand off the contact (you can use needle nose pliers to hold a little piece of folded sandpaper). Maybe you'll get lucky and they'll both work in their new socket :-)
I think bib's comment is spot on. It sounds to me like you are not providing enough power to the the ballasts to generate a plasma. Either you are consuming more power than can come into the house (you have an underrated breaker) or these are on a dimmer.