This is the art of soaring. Thermals are common and can be found almost everywhere, as you know. It is in thermals that you usually see birds circling without flapping their wings. In air masses containing enough moisture, cumulus clouds mark the tops of thermals, making them easy to find. Pilots typically circle in thermals just above the sailplane's sink speed, gliding from one thermal to another as desired.
Ridge lift occurs when a strong wind blows perpendicular to a ridge.
The wind flows up and over the ridge, producing an upward vertical component that can sustain a sailplane flying along the ridge off the upwind side of the top. Most speed and distance records have been set using this type of lift, since it does not require stopping to circle and because you can travel for a long distance - like along the length of the Appalachian Mountains. The third type of lift is a lee wave, where a very strong wind, under certain conditions, will cause an upward and downward oscillation of air downwind of a mountain range. This type of lift is more common in the western U.S. on mountain ranges like the Sierra Nevada. If you think that soaring may be too limiting for you, be aware that the world distance record is over 900 miles and the altitude record is just over 46,000 feet.