How about a friendly game of tennis?
Fresh air, some excercise, maybe a game of frisbee too or walk your dog (it's a big park)?
Bring your racquets and balls if you have them. If you don't have them, don't worry about it... we'll take turns heckling the players on the court.
Afterwards, we'll grab a bite/drink or whatever we're in the mood for.
Bring any extra racquets, balls, or whatever else you'd like.
Call me (Roger) if you can't find us. My cell is [masked]. Take this number just in case.