Been making my usual rounds the past couple days after returning from New England Quattro Club's driving school at NHIS. Noticed I'm getting about 20 mpg, about 2 mpg better than before the two track days.

Do you think it's just that I'm driving less aggressively because I got it out of my system at Loudon? Or is there a more mechanical explanation?

Me too. After getting 18-19 mpg all winter I got 22.3 mpg my last tank..

That is actually a very common observation. With all the daily driving in urban areas by going short distances your exhaust system may collect a few sediments over time.
What usually happens on the track is that the car will generate enough heat to "clean and clear" the exhaust system. Now your car can "breathe" a bit better and it is also shown in better gas mileage because of that.

So there is a possibility that in a few months down the road your gas mileage may go down again.

What we've done in the past is take the car on the Autobahn for short high speed ride (45-60 minutes), mostly every other month and clear the exhaust system. Same effect as your track day experience ;-)

Do you have some pics from the event? And how was it anyway?

While drinking a German beer? Hmmmmm....with a Pizza on the back seat, yes, I'd agree ;-)

It was a blast! I was a bit nervous going in (my first track event). After the first run I was thinking, Hey, I'm glad I tried this, but who knows if I'll ever do it again. By the end of the first day I couldn't wipe the grin off my face and couldn't wait to come back in the morning!
Started real slow. First couple runs I was barely keeping up with the last car in our green group, but by the end I was lapping the same car.
My favorite part of the track was coming out of the bowl (turn 6) all the way through the north chicane onto the front straight. [Got some nice comments on the V8 roar :)]
I was OK in the south chicane coming into the back straight but had some trouble getting the braking just right into the hairpin (turn 3).
Was hesitant going into the first turn and into the bowl (turn 6). Afraid to come in too hot, ended up braking a lot. This is where I think the heavy wagon held me back.
My instructor was quite good. I rode with him in his Subaru sti a couple times. He was very smooth and quick. I think I learned the most on these ridealongs. Got the "feel" of the line rather than just a lot of talk that didn't mean much to me.
Lots of nice cars (and great guys). I was the only wagon. Several beautiful S4s, nice A4s, a TT, some vintage Quattros, plus an M3, a Mini (same one from winter event), a classic Vette, couple of Porches, an old Mustang and �- believe it or not �- a Ford Focus!
Still planning on Mount Tremblant in October. Will try to get to at least one other event before then.

That is some real good news and I can imagine you with a big smile on your face, it is the best side effect track days have and people start to realize what they've missed in the past.
Keep the momentum going and practice on the road when ever possible. I'm just glad that you and your car are O.K., so the brakes are still in good shape and not burned out yet?

There are 2 PDA events coming in May, Pocono and Watkins Glen....I'll post pics or movies.

Would love to ride along with you some time and get an idea how a pig can fly. :)