"Shall we visit our nation's capital city for spring break?"
"What a capital idea!"
"How much capital do you think a trip like that would take?"
"It would be worth it to see the cherry trees in blossom around the capitol building."
Yes, the name of the building where a state's legislature meets or where the national Congress meets is spelled with an 'ol' while all other usages including the name of the town where the capitol is located are spelled with an 'al'.