Don't know if I can think of 5 but anyway:
1) Walk around the Monkey Forest.
2) Take in a show, think the recommended one had something to do with Fire.
4) Take a trip outside Ubud to the surrounding temples.
5) Visit a wood carvers outside Ubud.
Sorry I can't help you more, I was only a short time there. about 6 years ago
Ubud is great for just chilling. And this is why it remains one of my favourite places in the world!
Take a great book to read, hire yourself a private villa (www.agoda.com), and relax. Read a book, write your journal, swim in your private pool, paint with watercolours and then slowly venture out and take in some nice restaurants and cafes. (My favourite villa is Chapung Sebali).
If you feel inclined to do something slightly cultural (and not take my slothful advice) - then see one of the very many performances; Legong Dance, Kecak Dance, Ramayana play etc.
My husband went stir crazy during one visit and enrolled in a gamelan course. That was fun (for me).
We have also hired bikes and cycled around the magnificent rice fields and mountains.
Eat dinner one night at the amazing Miros, drink chai latte at Bali Buddha and stroll through the streets. Stunning clothing and homeware shops line most of the streets. about 6 years ago