Is this coolant leak normal?

Last Saturday morning, after driving the F355 with other F-car owners pretty spiritedly for approximately 2 hours, we stopped to have an hour long breakfast. After breakfast, while pulling out of my parking space, another driver noted a 1 foot X 1 foot pool of green liquid that had apparently leaked from my car. I noticed that after starting up my car, it was idling strangely for about a minute or so and then the engine behaved normally. Along with the group, I drove in slow traffic for about 15 minutes to another destination and did not notice any overheating, as the oil and water temp guages remained within normal limits. After stopping at the next destination, a car dealership for approximately 1 hour, I started my car up again and did not notice any coolant leak or strange idle. I then drove home on the freeway for about 30 minutes with no problem. After checking my coolant level the next day with the car cold, I noticed the level to not be low (only about 1 inch below the filler cap). I just had my yearly fluid service less than 2 months ago. Is it normal for coolant to leak spontaneously after driving the car as I've outlined above. And if there was a significant coolant leak, How come my coolant level does not appear to be low. I've had the car for more than a year and never had this happen before. Is this something to worry about?