QI Season 15 Episode release dates & where to watch

1. Ologies

In the first episode of the 'O' series, Sandi Toksvig sets out in search of 'Ologies' and 'Odoxies' - and finds out how an amusement arcade helped to win the Cold War, meets a lizard with three eyes, and much else besides. The guests are Bill Bailey, Phill Jupitus, Claudia Winkleman and Alan Davies.

2. Organisms

Sandi Toksvig looks at multiple Organisms. Where else are you going to meet the world's deadliest hunter, a photographer hidden inside an ox, and a juggling otter, all in the same room? With Nish Kumar, Cariad Lloyd, Holly Walsh and Alan Davies.

3. Oceans

Sandi Toksvig looks at the oceans. Tune in to hear one publisher's suggestion for a radical improvement to Moby Dick. With Aisling Bea, Joe Lycett, David Mitchell and Alan Davies.

4. Over and Ova

Sandi Toksvig looks at over and ova. Learn some tricks you can do with eggs, meet a flying pig and join in as the studio audience sings along with western film themes. With Bill Bailey, Jan Ravens, Grayson Perry and Alan Davies.

5. Odorous and Odious

Sandi Toksvig considers all things Odorous and Odious. Why is the world's second-smelliest man so frustrated? Sandi has the answer. With Nish Kumar, Sally Phillips, Ross Noble and Alan Davies.

6. Odds and Ends

Sandi Toksvig considers various odds and ends. Ever wondered how to tell a schnauzerorgan from a paddywhack? With Matt Lucas, Romesh Ranganathan, Liza Tarbuck and Alan Davies.

7. Opposites

Find out how to sort the sheep from the goats, discover the opposite of Tarzan, and meet the telescope that points straight through the Earth. With Jimmy Carr, Colin Lane, Sara Pascoe and Alan Davies.

8. Operations

An unconventional look at the theme of Operations. With Bill Bailey, Katherine Ryan, Rhod Gilbert and Alan Davies.

9. O Christmas

Sandi Toksvig hosts the QI Christmas special, with Jason Manford, Romesh Ranganathan, Holly Walsh and Alan Davies. Learn the best way to wrap an awkwardly shaped present and how to get wine stains out of the carpet.

10. Origins and Openings

Sandi Toksvig looks into some origins and openings, with Josh Widdicombe, Susan Calman, Rich Hall and Alan Davies. Tune in to hear what Mr First thought of Mr Second, and much more.

11. Objects and Ornaments

Sandi Toksvig looks at some objects and ornaments. Along the way, discover where you can find an actual UFO and meet the world's best-dressed crab. With Sarah Millican, Cariad Lloyd, Alice Levine and Alan Davies.

12. The Occult

Sandi Toksvig looks into the occult. Ever wondered how a Hand of Glory can make you rich? Sandi has all the answers. With Aisling Bea, Russell Brand, Noel Fielding and Alan Davies.

13. Omnishambles

Sandi Toksvig organises an omnishambles with Josh Widdicombe, Stephen K Amos, Cally Beaton and Alan Davies.

14. Oddballs

Sandi Toksvig looks at some oddballs with Jason Manford, Jimmy Carr, Victoria Coren Mitchell and Alan Davies.

15. Occupations and Offices

Sandi Toksvig looks into occupations and offices with Deirdre O'Kane, Richard Osman, David Mitchell and Alan Davies.

16. Overseas

Sandi Toksvig ventures Overseas to find out about who keeps their brothers in a cage, and much more. With Bill Bailey, Colin Lane, Desiree Burch and Alan Davies.

17. VG Part One

A compilation of some of the best bits from Series O, with Sandi Toksvig and Alan Davies.

18. VG Part Two Finale

More of the best bits from Series O, with Sandi Toksvig, Alan Davies and guests.