I wonder if it is possible to donate reputation points.
Yes, but only to someone who's answered a question. You can do this by setting a bounty on the question and then assigning it to the answerer. (I am not entirely sure whether you get to choose who gets the bounty if the question isn't yours, but I assume you do.)
May I offer a simple alternative?
Up-vote useful questions and answers.
- We can "donate" hundreds of points. We can upvote 30-40 questions/answers in a day; we get a few more if we vote on questions.
- We can direct the points towards users who deserve it.
- We can draw attention to useful questions/answers.
The daily limit resets at 0.00 UTC time. I try to use my unused up-votes before the reset.
There are a lot of great answers that go virtually unnoticed because they were quickly "accepted" and dropped off the front page.