There is a group organized to trek Mt. Nyiragongo and camp at the top near the active lava lake.  We have been able to negotiate a discounted trekking permit of $270 (usually $300) with Virunga National Park for this trip.  We will depart Gisenyi, Rwanda, on the morning of the 19th, have organized transport across the DRC border to the start of the hike, and organized transport back to Goma, DRC after the hike.  Additionally, we have organized for arrangement of DRC Visas, hot meals for dinner and breakfast, packed lunches, porters, and sleeping bags (if you need one) with Okapi Tours.  This is $175 ($170 if you have your own sleeping bag) per person, in addition the $270 trekking permit.