My first roll of home-developed film, Lomography Potsdam 100 in medium format on my Yashica A TLR. At the Kentucky Rennaisance Fair, of course. I used the Ilford Patterson kit at the recommendation of the photography store nearest me. While the initial investment was a little high, with an Epson V600 scanner and Silverfast 9 as part of the purchase, the ability to develop my own is such a cool and more affordable experience.
Special shoutout to Bethany for helping to get my finances in order and encouraging me to invest in the setup.