The Admission Free Festival features a wide, constantly shifting selection of performances, exhibitions, installations, projections and public readings. Projects presented at the festival reflect the current affairs of Celje and its citizens as well as broader social developments. Each festival centres on a common theme decided upon in advance. The jubilee 10th edition of the Admission Free Festival in 2009 addressed "intolerance", and other themes include "collectivism", the impact of sound on art, and "shame". The 2016 festival was themed "nature and light" and featured close cooperation with the Lighting Guerrilla Festival. The 2018 version was dedicated to long-time Art Society of Celje member Adolf Mljač, and the theme of the 20th anniversary was "a look back".
The festival initially featured works primarily associated with the Art Society of Celje, with society members Franc Purg, Manja Vadla, Željko Opačak, Andreja Džakušič and Simon Macuh playing a very active role. As it has grown, its scope has broadened, and recent festivals have featured works by artists from Bosnia and Herzegovina, Japan and Belgium. The participatory nature of the festival is underscored by the active participation of students from the local high school, who in recent years have had an opportunity to collaborate with established artists in workshops and street performances.
Festival interventions regularly involve the public. For example, at the 12th edition of the festival, visitors were asked to bring sleeping bags to participate in Simon Macuh's work Bedroom – Good Night and Pleasant Dreams. In 2018, artist Jusuf Hadžifejzović set up his inquisitive Emptiness Shop in the framework of the festival, where guests could buy and sell "emptiness".
An important aspect of many projects is also hospitality and gastronomy. At the inaugural festival in 1999, Željko Opačak hosted Take a Little Piece of my Heart: featuring works by Andreja Džakušič and Boris Oblišar, the installation expressed how the co-operative participation of food by both the artists and the public creates new social spaces. At the 2013 festival, Mark Požlep presented his Drunk Cook Book and Manja Vadla hosted a picnic.