There are many Halloween activities. My favorite one lately is "Boo-ing".
To start a Halloween BOO, you secretly leaves a small gift basket, a BOO poem, BOO instructions and a BOO sign on someones doorstep or desk.
The lucky BOO-ee is asked to post the sign near the door, alerting others that "We've Been BOO-ed!" That way, new BOO recruits won't leave a duplicate BOO on the doorstep/desk.
In turn, they are asked to BOO two other households/co-workers, leading to a chain reaction and Halloween fun.
READY, SET, GET BOO-ing!!!!!