When I was young I never had a specific place to play with my Lego, usually I used my desk, with the disadvantage that I had to clear everything at the end of the day or before.
I introduced my kids to Lego very young, they were almost three years old, at first they used an old Ikea center table, but quickly it became clear that they needed a bigger platform:
It was time to build a table, the main idea was to have a place where they could build and play, but also be able to let everything in place so they could continue at any time (the same day or any other day). They were young and I didn’t want to deal with bricks all over the floor, or at least minimize the quantity of bricks laying around, so the table had to have raised borders to stop the parts from falling.
I had a chipboard panel with white melamine, 26”x66”, and some ½”x2” pine for the borders, so I started with that. It went directly over the Ikea table:
After a couple of years my son was in need of some storage space, he had grown up too, it was time to raise the table and include a drawer. I integrated the drawer in a way that the outside panel would be raised and be at the same level the platform borders were, this way it would be easy to push all the bricks from the platform to the drawer without making anything fall to the floor:
Since then the table and bricks moved to the basement, and just last week a friend gave them a big industrial desktop, 35"x75", the cargo train is no longer on the floor.