Recommendations for a trip to SJ (San José)

Hi there! I will be travelling to Costa Rica for Surfing in November and I'm planning to stay one day and two nights in San Jose before heading to the Pacific coast.

I will be arriving at 8 pm on the 31st October. Are there any Halloween partys or do you guys have any recommendations where to go that night in SJ?

Also I'd like to do a guided walking tour on Friday, 01 November. Do you guys have any recomendations for that, too?

Muchisimas gracias!!
Paul