Nothing is more hip than knowing how to throw a good party, and no party is more stimulating than an art party. Making an art party happen will be best if you can represent artists of various mediums -- music, film and sculpture, for example -- so that the different art forms are not competing for physical or audio space. You may play art games, such as exquisite corpse, at the party too, since all will be inspired to make art after seeing the main exhibitions. Try decorating cookies or group mural-drawing for other art-related party activities.
Participatory, interactive art is a hot form of art-making. Interactive art draws individuals who may otherwise find art boring, and also makes a statement about what art is "supposed to be." Everything from interactive video to interactive kinetic art will accomplish the task of inviting viewers to participate directly in the creative experience. Sometimes, interactive art can even result in a group-created final piece, or in individual pieces that participants can take home with them.
Many "hip" art activities begin in urban areas, so take a look at what's going on in urban areas near you. Visit galleries there, but also look for live art-making on the street, such as performance art activities, graffiti-mural making, and art-music shows. You can incorporate these ideas into your own art activities, and begin to spread the trend beyond its original context.
Environmental concerns are extremely relevant today, and it's very hip to be environmentally aware. Incorporate this into your art activities by basing them around recycled materials or environmental themes. You may lead a group to pick up trash along waterways, later to be sorted and used for art or else appropriately discarded. You could also turn garden-planting into an environmental art activity by planting into rows that form a particular shape when viewed from above.