I got my first probe into orbit of another planet (specifically, Duna). I used what I learned about rocket design from Scott Manley's intro videos (especially the Minmus lander one) and built a modified version of his rocket around an unmanned probe. Strapped a Science Jr. and some goo containers on it, and managed to make a pretty tight transit. Unfortunately I ran out of fuel just as I was about to enter a stable, if highly eccentric, orbit of Duna and had to use RCS to circularize myself. After that I just spent the rest of my RCS fuel slowly decreasing the size of my orbit to about 1,000km. Got myself a couple hundred units of science out of it, now I'm going to start an Eve probe of similar design, and then work on building my first space station in Kerbin orbit.