happening

present participle and gerund of happenform-ofgerundparticiple

• From the ground, Colombo’s port does not look like much.[…] But viewed from high up in one of the growing number of skyscrapers in Sri Lanka’s capital, it is clear that something extraordinary is happening: China is creating a shipping hub

Busy, lively; vibrant, dynamic; fashionable.slang

• “[…]San Francisco is not exactly the most happening place, you know.”
• When the show ends, the circular, sunken floor is one of the more happening dance clubs in town.

Trendy, up-to-the-minute.slang

• Every show has its hottest, most happening trends. If I were to isolate just one for hardware and one for software, this year's hot hardware would be the 386 machines, and the happening software would be desktop publishing.
• San Antonio is the newest, tiniest, and most “happening” wine appellation in Chile, with just four boutique wineries that focus on quality, not quantity, producing fine pinot noir, sauvignon blanc, and syrah.

Something that happens.

• Three follow-up singles, all ecological or religious in theme, did chart in the lower reaches of the Hot 100. Thereafter, Ocean remained a Canadian happening.

A spontaneous or improvised event, especially one that involves audience participation.

• And it was some kind of happening / Some kind of happening / Salvador Dali's garden party