A charity rally, the Rhino Charge is an annual event hosted by Rhino Ark (www.rhinoark.org) to raise funds for conservation of the Black Rhino, among other projects. It happens in secret locations - only revealed the week before so as to keep the competitors in the dark about the terrain - around the 2nd week of June each year.
A truly exhilarating event, the Charge involves camping, hiking, partying, and some of the most memorable off-road driving you'll ever see.
If you plan on attending, try Bunduz Adventure Tour operators (www.bunduz.com). They provide camps and help with booking.