Have you ever marched, ridden on a float or otherwise been in a big parade?

Yeah I built floats and the family and I entered them in the Parksville Sand Castle parade 2 years in a row. I didn’t win anything the first year but the second year I won the first place ribbon and another ribbon for most original. It was a lot of fun plus it generated a lot of grounds keeping business. Cheers!

No I haven't.  My children and I did camp out all night for the Rose Parade in Pasadena California more than once. We had great spots near the judging stand and were able to see most of the performances. I do have to say even with blankets, the ground was very cold, but we all had a wonderful time.

I marched in a Memorial Day parade with one of my nephews when he was in Boy Scouts.

  I was in the Webelos, the Cub Scouts, and the Boy Scouts, all before the age of 14, and I marched in at least three parades.

  When I joined the Marine Corps, I was in several parades during my time on active duty. Two memorable ones were in The Philippines when we conducted a Pass in Review that was attended by their then-President Enrile, and another one was a last-minute notification that I would be in the Color Guard at the local Memorial Day Parade in downtown San Diego. 

  As a law enforcement officer, I was an advisor in a program called the Explorer Scouts, wherein youngsters ages 9 to 15 learned about careers in that field of employment by participating in events led by officers. Parades were one of the many, many things we did. I also matched in at least three of the annual parades commemorating the birthday of Reverend Martin Luther King, Junior Day.
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I have.  Once.

As a young sailor in Navy electronics school, we were bused to Grant Park in Chicago to march in a parade there.

Yes in high school, our towns Halloween parade but I cannot remember why. It was likely a group from school I was in. I remember throwing candy to the kids.  And thinking afterwards, that I preferred watching it as to being in it. 

I was also in a group (not school related) that sold refreshments at the parade several years. 

I've never been on a Carnival float but in many years past used to help run a miniature railway temporarily set up for the town's annual Carnival Day.

The whole Carnival was a full day event in Summer, with various activities, air-displays and side-shows until the Procession, never called a "parade", in the early evening, and finishing with a fireworks display later, after dark.

The railway belonged to a local, amateur model-engineering society. It was not a commercial side-show; but gave rides to paying public passengers, mainly children.