The Brighton Museum and Art Gallery occupies the stable block of the Royal Pavilion, which makes for an unusually glamorous setting. The collection is wide-ranging: Egyptian mummies, Fabergé eggs, a room devoted to Art Deco and Art Nouveau design, and a gallery of fashion through the centuries. The building itself underwent a major renovation in 2002 and the galleries feel fresh and well-curated.
Admission is free, which means you can treat it as a rainy afternoon refuge without guilt. The fashion and style gallery in particular rewards a slow wander — there are dresses and accessories spanning three centuries, arranged to show how silhouettes and materials changed with manufacturing technology and social convention. The café in the former palace stables is a good place to stop.