I would climb inside it and try to fly. 

The next poster gets a whole tents worth of fireworks. 

They would be carefully dispersed and set off for the enjoyment of a number of people I know.

The next poster receives a life-size statue of a cougar.

That's going in my living room (if I had a living room :P)  Ohhhh... I would probably make a life size North American wildlife diorama/display in my living room.  That would be so cool!

The next poster finds a dragon egg.

I first try to sell it to a butcher, but it ends up hatching, so I name the dragon Saphira. Wait... I feel like I've heard this story somewhere before ?

The next poster receives a pair of tickets to the middle of Antarctica  

I'd strongarm someone into going with me - or maybe just ask my dad, he'd like to go.  

The next poster is given the opportunity to go to the moon.

I’d go with my camera and take all the pictures. 

The next poster is given a slightly used dining room table. 

I would be very happy, as long as I could get it up to my apartment.  

The next poster is asked to make breakfast for a large group.

I'd invest in lots of eggs, bacon, sausages, baked beans, tomatoes, mushrooms and hash browns and make them a full English fry-up! Yummo.

The next poster discovers a gold nugget in the stream at the bottom of their garden.

First, I'd be impressed by the stream and the garden. I would wash the nugget off and wonder what it was doing there, maybe get it appraised - but very carefully so there's no gold rush (and then no garden left ).

The next poster inherits a locked trunk - but no key.

I would unscrew the hinges. If that didn't work, my curiosity would probably drive me to sledgehammer the lid open!

The next poster finds a bird's nest in their mailbox.

I'd very carefully move the mailbox to a nearby tree where it's safer for the birds, then get a new one for the mail!

(This incidentally would have to be at my family's home in Australia, where we usually have letterboxes — as we call them — outside our houses, by the front gate or driveway. Here in the UK people only have a slot in the front door for the mail, so I don't think you'd get many birds nesting in that. )

The next poster is given a painting of a sailing ship — one that looks remarkably like the Dawn Treader...

I try to find a place for it.

The next poster is invited for a week out at a country house.

I have a lovely time exploring the countryside during good weather — but when it rains, I can't resist looking into all the wardrobes in the house, just in case...  

The next poster is offered the opportunity (for free) to do a tandem skydive!

I would think seriously whether it was worth both the current and intrinsic risks - and probably pass.  

The next poster is handed a python to hold.

I’d hold it and pet it and think it was rather beautiful. 

The next poster gets a job offer from Netflix to help on the Narnia projects.