I had the Blue Angels set. Far me it from this Navy brat to have the Thunderbirds! 
Actually, before the F-4 Blue Angels team kit, I had the F11F kit.
Does LEGO count? 
I got a Fallingwater set a couple of years ago, and I’ve never opened the box.
I moved a few months ago and don’t have a dining room table anymore, but I have a little fold-down kitchen thingy that I might be able to build it on…hmm…
My model of Galileo met it’s destruction the New England way with a snow ball. Must have taken me an hour (with a very sore arm and cold hands) to hit it, but once I did, there was no hope of repair. That bad boy exploded!
My brother bought me one of those. It sat around for about 15 years in the garage - then I found that the box had disintegrated.
I’ve done a Guggenheim museum and Empire State Building in that series. They take about fifteen minutes to build, the downside, but they look great.
15 minutes? Seriously? 
I was hoping for a nice several-week project. Oh well. I guess I’ll figure out where to display it first, then.
I’m fast. 30 minutes tops though. That’s why I don’t buy more Legos stuff - they are cool, but too easy to build.
Now, if you want a real challenge, you can try something my daughter got me for my birthday. It is a wooden model of a generic St. Petersburg church, inspired by our visit last year. It consists of 8 or 10 pieces of plywood with the pieces embedded, and the only instructions are a picture of all the sheets on the back with numbers associated with each piece which more or less tells you the order to glue stuff together. Getting that thing together is the height of my puzzle doing career, It is definitely a several week project. And when people see it they will be impressed.
Here is the kit - I think. After I finished it I saw the kit in a thrift store - I can imagine people getting it, seeing the lack of directions, and freaking out.
By the way, if you like to do buildings, Puzz3D 3d jigsaw puzzles take considerably longer than 15 minutes. Start with a small one. I’ve done tons. Avoid ones with rounded bottoms - the Star Destroyer model and the space shuttle model. They don’t really work. My wife wrote some copy for the company which makes them, and they admitted as much.
I got back into model rocketry (one of my hobbies when I was a teenager, in the late 1970s and early 1980s) six years ago. All of the rockets I’d had back then were either thrown out or given away by my parents in the intervening 25 years, and so, I had to re=start my collection from scratch.
I bought a ton of kits (and built a ton of kits, too), but I probably have 20-25 unbuilt kits in a tote in the basement – a mix of new Estes kits, some vintage Estes kits (bought on eBay), and some kits from the smaller, modern-day companies (like FlisKits and Semroc).
I haven’t built a kit in at least a year, but I’ll probably get back to working on that “slush pile” of kits over the winter. 
I collected model kits for several years from the early '90s to the early '00s, but only built a handful of them. I just kept waiting to have space to build a nice workstation for building them, but it just never happened. I wound up selling off dozens of kits on eBay, averaging about $0.10 on the dollar versus what I paid for them. Still, it got them out of the house when I was tired of looking at them, after having moved them about 4 times over two states.
Around 1980, a hobby shop near me had a going-out-of-business sale, and I bought a bunch of Aurora Superman and Superboy model kits for a dollar each. After assembling one of each as they were supposed to be done, I got creative. Using Superman kits, plastic putty, and other odds and ends, I built models of Green Lantern, Hawkman, and Adam Strange. From Superboy kits, I built the Flash and Black Lightning.
I still have the unassembled pieces of one more Superman kit (but not the original box, unfortunately).
I have a Lamborghini Diablo model kit around here somewhere. My dad gave it to me 20-something years ago when I turned 16 as a gag gift. He said, “Hey you asked for a car, you just weren’t specific enough!” 
One of these days I should dig it out and put it together.
Thanks, Voyager; I’ll check out the Puzz3D stuff!
That’s pretty much exactly what my mom said when she gave me a Hot Wheels Corvette on my 16th birthday. 
If you had built a Supergirl out of those pieces I’d be really impressed. 
I have an Airfix * HMS Victory * 1:180 scale and a * HMS Hood * 1:600 scale and waiting for paints and time to be completed
Especially a fully functional one.
That’s pretty cool! Figure conversions are a lot of fun.