Assuming you wear light or silky undergarments and there is no constant air flow/current in the room:
1. Take off your undergarment. No one else is there, you don't need it anymore.
2. Tear apart your undergarment into as many small pieces as you can. Use your teeth if necessary. Let them dry to prevent clumping later. Make it an odd number to prevent you biasing the results, later.
3. Stand up straight. Place your feet together. Cup undergarment fragments in your hands at chest level.
4. Extend your arms, still cupping the fragments. Keep the center of your cupped hands on your plane of symmetry (in line with point at which your feet meet).
5. Drop fragments.
6. A. If more fragments land on the right side of the plane of symmetry, write 1.
6. B. If more fragments land on the left side of the plane of symmetry, write 0.
7. Repeat as many times as necessary for the number of random bits required.
Upside: you can do this in the dark (problem did not mention if a light source was readily available or not).
1. Take off your undergarment. No one else is there, you don't need it anymore.
2. Tear apart your undergarment into as many small pieces as you can. Use your teeth if necessary. Let them dry to prevent clumping later. Make it an odd number to prevent you biasing the results, later.
3. Stand up straight. Place your feet together. Cup undergarment fragments in your hands at chest level.
4. Extend your arms, still cupping the fragments. Keep the center of your cupped hands on your plane of symmetry (in line with point at which your feet meet).
5. Drop fragments.
6. A. If more fragments land on the right side of the plane of symmetry, write 1.
6. B. If more fragments land on the left side of the plane of symmetry, write 0.
7. Repeat as many times as necessary for the number of random bits required.
Upside: you can do this in the dark (problem did not mention if a light source was readily available or not).