Please help, -smoke?

[EB847]

I just got a 2000 Boxster S with 35k mi. It has been maintained by the local dealer and even had the 60k svc done at 24k. Last oil change was 3k ago and will be done soon.

My question: Yesterday morning I took it out for a 15 minute drive with no problems. Then I went to fire it up later in the afternoon, and quite a bit of smoke came from the exhaust (white-smelled like exhaust). This had never happened before and the engine sounded normal. I immediately checked for any warning lights and shut off the engine. There were none. I double checked the fluids and all was well. I restarted a few minutes later and it did not happen again. I drove for about 20 min with no problems.

Anyone ever have this happen? Possible causes?