The Hussite Museum fills the old town hall on Žižka Square, which is exactly where it belongs. Its exhibitions explain Jan Hus, Jan Žižka, the Hussite wars, and the religious and military movement that gave Tábor its reason for existing.
The building matters too: the town hall is one of the old square's finest late-Gothic monuments. Combine the museum with the underground tunnels below the square rather than treating them as separate outings.