Kamloops is a good base for exploring the BC interior. The most rewarding day trips:
Sun Peaks (45 min north-east) — skiing in winter, mountain biking and golf in summer; see the dedicated POI.
Adams River sockeye run (90 min east, near Chase) — every four years, in early October, around two million sockeye salmon turn the Adams River bright red as they return to spawn. The dominant run year is the experience of a lifetime; even off-cycle years are worth the drive.
Wells Gray Provincial Park (2.5 hours north on Highway 5) — the "waterfall park", with Helmcken Falls (a 141-metre drop, four times the height of Niagara) and a number of other major cataracts, plus excellent canoeing on Clearwater Lake.
Kamloops Lake (30 min west, along the Trans-Canada) — a long fjord-like lake that the South Thompson opens into, with several beaches and viewpoints, plus the small wine region of the Thompson Valley.
Cariboo Gold Rush trail (north on Highway 97) — the road from Cache Creek up to historic Barkerville runs through striking dry country; a full long day or better an overnight.