Just open one. It stays your money until you use it. You don't even need to tell them about it. Virginia is the best.

Has anyone ever set up a 529 for someone other than a child or grandchild? Planning to do so for our niece and nephew (whose parents are not in a position to do so). Any tips? We will likely be the main contributors, though other family members may chip in from time to time. We'll likely pick a state plan based on low fees (so far Nevada and Virginia are looking good to us). Would welcome advice!