Assuming that you have accommodation sorted but no plans for Saturday 23 September..
The Color Run is the oldest and biggest 5k colour fun run in the world. You don’t need to actually run the 5k, you can walk, dance, whatever. Ticket prices on the website or you can just get to Madeira Drive or the seafront and watch.
Royal Pavilion is £13.00 per adult, £7.50 child 5-15 yrs £7.50 at the entrance £11.00 concessions (bring confirmation) and family tickets are available. Most individual admissions tickets are 10% cheaper if bought on the website. Guided tour tickets £4.90 starts 14:30 BST Jane Austen by the Sea exhibition is free. Royal Pavilion Gardens Greeters will be out in the gardens giving info on Brighton museums. If your group is in Brighton for the weekend, group tickets are available.
Brighton Museum is situated in Royal Pavilion gardens and tickets are cheaper if bought online – or there’s an option of buying a two day history pass for the museum, Royal Pavilion and Preston Manor. If your group is in Brighton en masse, group tickets are available.
There’s a World Stories: Young Voices exhibition, featuring young people from Brighton and their connections to other places. If you have kids with you there’s a World Stories Gallery Family Trail PDF
Galleries include Brighton, Ancient Egypt, 20th Century Art and Design, Brighton & Hove Albion FC (newly promoted to Premier League), Fashion and Style and more. There’s a temporary exhibition, Constable and Brighton.
Saturday 23 September 10:30 – 16:30 there’s an African Fashion: Wikipedia Edit-A-Thon
If you drove to Brighton or can get a cab (10 mins from Brighton Marina), there’s a Nostalgia and Collector’s Fair at Ovingdean Village Hall, Ovingdean Road BN2 7AY 10:00 – 14:00 free admission, parking and wifi.
Saturday night, at Junkyard Dogs, Edward Street, Brighton BN2 0JG is Cards Against Humanity, a bizarre sounding pub quiz with free entry for a team of 4 or less.
Odeon Brighton (situated in the city centre) will be showing the newly released Borg vs McEnroe and Kingsman: The Golden Circle.
Cineworld Brighton can be found at Brighton Marina Village. Getting There and will be showing American Assassin, Beauty and the Beast, Borg vs McEnroe, Cars 3, Despicable Me 3, Dunkirk, IT, Kingsman: The Golden Circle. mother!, The Jungle Bunch, Victoria and Abdul.
Duke of York’s Brighton Picturehouse will be showing Borg vs McEnroe, Molly Monster, mother!
Dukes at Comedia Picturehouse Brighton will be showing God’s Own Country, IT, mother!, Victoria and Abdul, Wind River
The Volks Electric Railway on Brighton seafront is still undergoing restoration.
Brighton Diver boat is available to take groups fishing or to the wind farm on Saturday.