Last year I made 3 personal loans to some friends of ours. One was made in May, one in June and the last, biggest one was made last month, in December.
I receive monthly checks for these loans and I am counting all the interest that I make on them in my $20 challenge.

Yesterday, I received payment on the 3 loans. I made $481 in interest for just one month. I am charging them 4%, but that is better than they could get at the bank. (plus, no closing costs)

So my $20 challenge looks like this:

Prev. total $111.00
today 481.00
new total $592.00