Make friend with the people there and get to know more about Pekan. Tip:Adress the elderly man as "Uncle" and the elderly lady as "Aunty" I'm sure they'll be more friendly to you.
Read books-as there're not much of entertainment outlets.No Bar, no pub, no cinema, nevertheless, it's a good place for a good rest.
Star watching at the riverside, there's less light pollution in Pekan therefore you may see the sky clearly at night.
Sea fishing, ask the Chinese in town, don't be surprise they might have friend who own a boat for sea fishing.
Lepak-a culture of village people where they just laze around, sit and chat, or play guitar and sing with friends outside the house at anywhere, anywhere they feel comfortable...