Eighty years ago, this radio enthusiast/sports fan was able to attend the game and listen to the play-by-play broadcast from the stands, thanks to this one-tube pocket portable, described in the September 1940 issue of Popular Science. The set was billed as being only a little larger than a tobacco tin, and was constructed from cigar box wood. The antenna was a loop wound around the box, and it was said to be able to pull in stations up to fifty miles away.
The circuit was superregenerative, and used a miniature 958 tube, which is likely unobtainium today. The B battery consisted of four penlite cells, and the A battery was a normal flashlight battery.
I just found a 958A tube available on a site for $10. Not unobtanium quite yet!