Dissolve a sodium metal chip into liquid ammonia.
Sodium metal is all too happy to donate an electron in most circumstances.
This case is no exception, although the location to which the electron is donated is a little unusual. Ammonia's liquid lattice has a recurring gap with a radius of about 3.3 Angstroms. Through a fortunate orientation of the dipole moments within the lattice, this space can actually accomodate an electron. Sodium donates the electron to the gap, even though the electron doesn't bond to the ammonia. This leaves an uncoupled electron in solution, the solvated electron.