My nephew got married at Christmas and his sister has a now 3 month old baby. They asked me to look after the baby for the day which was great fun. I got him when they arrived at the church she fed her in between and then I had her again during the reception which she slept through in the corner near us.
You might find an aunt who would love the job of looking after your baby for the day. Until the day I hadn't seen her as they live interstate and that wasn't a problem.