I've never tried normal boiling or roasting chestnuts, but I frequently microwave them. Piercing the shell is fairly important, or they explode like popcorn, only more violently (and with more mess).

I put two or three chestnuts in a small bowl and just barely cover with water (maybe a little less). Microwave on high for 45 seconds to 1 1/2 minutes, watching carefully. Stop cooking after the water has boiled 10 seconds, and peel. Timing will vary depending on initial temperature of the water, size of the nuts, and amount of water in your bowl. :)