In the episode where Liz has the 'radio date' Max gets drunk and whisks her away to confess his feelings. He turns the streetlight into a discoball etc and sets off fireworks from parking meters by touching them. In slow motion you can clearly see the sparks begin to fly before he touches the parking meters.
In the episode when the "skins" make everyone in Roswell disappear, Liz and Maria are looking down the high street with max I think. It is meant to be deserted, but on a shot of Liz, you can clearly see police cordons, people and cars going by. deserted, mmm!