How to do this present?

[Pikachuwithyourmouthclosed]

Dh and I are giving the children a climbing frame for Christmas. Its a complete surprise. They will be thrilled. I can barely hold dh back from telling them - i think he's more excited than they will be!

It's arrived. It has to be assembled. So, do we...

1. Give it to them unassembled and put it together on Christmas day? (Family project)
2. Tell them on Christmas eve and assemble it then so it's ready for Christmas day?
3. Somehow put it together without them knowing so it appears like magic on Christmas morning (this is my favourite option but it's impossible to work out how to achieve)
4. Other option i haven't thought of.

If ye are not the quick building type get someone who is to help on Christmas Eve. My db has done that for us on a few occasions. He sees immediately what needs doing ..we don't!! Saves a lot of hassle and time.

We did a large trampoline once on Christmas eve after bedtime in the snow. It was bloody awful! That said I'd do it again because it was so magical for the dc.

For a climbing frame, won't it need time to be cemented in the ground?

Couldn’t make it together be a fun Christmas Day activity? ‘Fun’. I mean my dh wouldn’t like a crowd watching and cheering him on. But yours might.