More than 100 people descended on SportsAble in Braywick Road for the fair which was opened by archer Kathy Critchlow-Smith.
Party-goers enjoyed music from Burnham-based Pop Goes the Choir as well as Sima's Action Kids at the event yesterday.
It was held for Ethan Quinn, of Wendover Road, who suffers from cerebral palsy.
His parents Karen and Wayne are trying to raise £50,000 for a pioneering operation which could help the youngster walk without splints as well as improve his mobility.
The family has already raised more than £27,000 through various fundraising activities such as fun days, shopping events and donations.
Karen said: "We have been absolutely overwhelmed by the support we have received and people's generosity."
The appeal received another boost on Tuesday with a donation of more than £180 from the 1st Lent Rise and Dorney Beavers.
The group, which Ethan also attends, raised the cash through a Scoot and Skate event in October which saw the beavers travel 72 miles around a playground on wheels.
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