I also recommed a visit to Lublin, if possible, for the VIth edition of the Lublin Jazz Fest. Especially the Saturday part of the program seems extremely tempting (Satoko Fuji Orchestra) while the biggest star of the festival - Ravi Coltrane - closes the weekend.
Harris Piano Jazz Bart 17th Birithday with Pawel Kaczmarczyk Directions in Music:
24.04. Tribute to Eric Dolphy with Maciej Obara
25.04 Tribute to Dexter Gordon with Piotr Baron
26.04 Tribute to Elis Regina with Maria Alban Juarez
Directions in Music is a series of projects led by Pawel Kaczmarczyk, designed to honor music of some of the most important figures in jazz history, in special, often very surprising arrangements, each edition is featuring a different band and a special guest. The three concerts (the fourth, dedicated to Hancock's Headhunters is taking place next weekend) will present quite a spectrum of jazz histroy. My bet is the most adventurous will be the concert with Maciej Obara but some classy bop and bossa nova should turn out fun as well.
25.04 Żywiołak at Piekny Pies
This band is one of the few representing the revival of folk music in Poland. Gritty, raw energy that comes from the ethnic instruments can battle any heavy metal band on the stage.
Satoko Fujii Orchestra, including some of the most active polish improvisers, plays on Saturday, Ravi Coltrane Quartet plays on Sunday. For the complete schedule check the festival's website lublinjazz.pl.