I live in a small house. Even using a small scale like N, I don't have much room for a large layout like I had when I was younger. That's where micro layouts have been a saving grace.
Micro layouts are small model railroad layouts that are usually no larger than 3-4 square feet. If you think about it, that's the same size as a coffee table. While they are a bit limited in the curve radius options, there are still lots of things that you can do in this small amount of space. The nice thing about a layout that is so small is that when you're done playing with it, you can put it up out of the way.
Below is photo of my layout which I plan on landscaping with my daughters this winter. As you can see, it's more than just a track loop with 5 turnouts/switches.
There are lots of resources out there with track plans and photos for ideas. Below are some links:
While most layouts use a base of plywood, particle board, or rigid foam insulation, I've seen some that use even more far out ideas ranging from cake platters to guitar cases to roulette wheels. If you don't believe me, just look at the photos below!
The layouts below are the work of Don Kriegbaum of Englewood, OH. The photos were taken at the 2016 N Scale Enthusiasts Convention.
As you can see, there are many possibilities. Use your imagination and see where it goes! Have fun with it!
Bottom line: If you've been wanting to build a model railroad layout but a lack of space has been holding you back, you don't have to let space be a factor. There are many ways to build a detailed and dynamic layout in a footprint that won't crowd anyone out.