In no particular order -
Horse Riding (can be booked in advance)
The beaches of the Berwickshire coast (St Abbs Head, Coldingham and Eyemouth are 45 minutes away) and Northumberland (Bamburgh castle and beaches along the coast) are about 45 minutes away.
Fishing on the Tweed, Teviot and Bowmont. Lessons can also be organised with World Team Speycasting Champion Eoin Fairgrieve.
Golf. Hirsel, Roxburgh, Kelso, Cardrona, and many more in between!
Beauty Salon (can be booked in advance)
Kelso has an Abbey, ice rink (with curling), and many shops, boutiques, coffee shops, bars and restaurants.
Kelso Rugby Club play in the National League 2. In fact, rugby is a big spectator sport in the Borders, with the world famous Melrose Sevens about 20 miles away, and similar tournaments in Kelso, Jedburgh, Hawick and Galashiels,
Floors Castle - the largest inhabited castle in the country, seat of the Duke of Roxburghe and impressive grounds. And a massed bands display (at the end of August).
Kelso Racecourse - National Hunt racing - Meetings regularly October to May.
Other Places in no particular order.
Mellerstain House - Beautiful stately home, open to visitors.
Jed Forest Deer And Farm Park - Great day out for families with a collection of farm animals, deer breeding, birds of prey (with displays and opportunities to handle the birds), lamb feeding, tractor rides and free roaming piglets for children to play with.
Hirsel Estate - A large country park near Coldstream, great walks.
Ford & Etal Estate - Other side of the border, but still pretty nonetheless! Pretty villages, walks, fishing, steam train, cycle ways etc etc.
Flodden Battle Field - Site of the last great battle between the Scots and the English (this time an invading Scottish army) in 1513, and the last battle where a British Monarch fell in battle (James IV of Scotland).
All the other Borders towns have things to do eg Jedburgh Abbey,Mary Queen of Scots House, Jedburgh Castle Jail Museum, Melrose - a pretty Borders town...etc etc etc.