Bouldering
Bouldering is climbing in its simplest form, sans ropes, harnesses and hardware on rock faces that are typically less than 20 feet tall.
Bouldering is great for beginners. It's relatively affordable, accessible and easy to do with large groups of friends, making it a great social activity. Unlike free solo climbing, which is also performed without ropes, bouldering problems usually less than 20 feet tall. Most climbers say anything above 15 feet is a highball and can range in height up to 35-40 feet where highball bouldering then turns into free soloing.
Gear
Bouldering requires significantly less gear than other forms of rock climbing. In fact, if you plan to boulder indoors at a gym, all you really need is a pair of climbing shoes, which you can usually rent at the gym. Other commonly used gear includes chalk to help absorb moisture from hands and increase friction when climbing and a brush for cleaning off holds. If you're headed outdoors, you'll also need a crash pad to cushion your falls.
Setting
A climbing gym is a great place to go bouldering for the first time. Climbers of all abilities can have a good time with many route options available in one place and accessible in any type of weather. For those who enjoy the outdoors and live near a crag (a climbing area that contains numerous routes), there are guidebooks, apps, and online resources to help locate problems which are graded based on their difficulty. Americans typically use the V scale, which grades boulders from V0 to V17.