Hunt street art in George Town. Start at Armenian Street and find the famous "Children on a Bicycle" mural, then wander the lanes for dozens more. It is free, and early morning gives you photos without crowds.
Ride the funicular up Penang Hill. The train climbs to 821 m for views over the island; return tickets are around RM 30 ($7) for foreign adults. At the top, The Habitat rainforest walk with its treetop canopy bridge is worth the extra ticket — it is the best nature stop on the island.
Visit Kek Lok Si, one of Southeast Asia's largest Buddhist temples, a seven-tier pagoda complex near the base of Penang Hill. Combine both in one half-day since they are 10 minutes apart.
Walk the Chew Jetty, a century-old Chinese settlement built on stilts over the water, and stop by the Pinang Peranakan Mansion to see how wealthy Straits Chinese families lived.
With kids, add ESCAPE Penang — an outdoor adventure park with the world's longest tube water slide — or the interactive trick-art museums in George Town. Skip Batu Ferringhi beach if you are coming from or going to Langkawi; the beaches there are better.
Above all, eat. Char kway teow, laksa and cendol at Gurney Drive or New Lane hawker stalls cost around RM 7-15 ($1.70-$3.70) a plate.