To have a blast

Idiom: to have a blast


Example 1- (last week) Don't forget to buy your ticket for the Beach Party! It's on Friday and we always have a blast, so you don't want to miss it!

Example 2- (this week) The Beach Party was so much fun! We had a blast playing beach volleyball, tug-of-war, water games, and the ALS Ice Bucket Challenge! I'm so glad I didn't miss it! I can't wait for next year. 

Meaning: "to have a blast" means to have a lot of fun. 
Grammar note: the verb have changes according to the necessary verb tense:
We will have a blast next week. 
We had a blast yesterday.                  @LSINE @LSIOC
We are having a blast right now.         @LSISB @LSILA