a plate of bite size pieces of watermelon, rockmelon, whatever is in season where you are, strawberries are plentiful here right now. especially in hot weather, bright colourful fruit goes down well.

i'd cut it up the night before, put in tupperware type containers, so on the day, if you're having a bad day, you just grab the tupperware, and icebrick and go.

another "no cook take a plate" idea, buy some dips and water crackers.
or cut up few sticks of celery and carrot plus dips.