One of those quite literally Once-In-A-Lifetime opportunities comes to an end in just three months time.
In August there will be a chance to go inside Clarence House, the official residence of The Prince of Wales and The Duchess of Cornwall.
Next month will offer a chance to take a trip down the Thames in a steam powered tug. The steam tug Portwey is one of only two twin screw, coal fired steam tugs now active, and is based in Docklands.
There's a tall brick tower that dominates the area next to the Thames at Kew Bridge, and later this month is a rare chance to climb it.
In August there is an event called Kids Week that offers free tickets to children to go to the theatre. Despite its name, it appears to last all month.
A series of WW2 tunnels under Clapham that were later used as a short term hotel for Windrush arrivals are being opened up for tours.
A mini-Highline is a step closer to be being built in Peckham following the completion of the crowdfunded feasibility process.
This weekend, the Epping Ongar heritage railway, at the end of the Central line, will be hosting a grand total of five steam trains chugging decoratively through the Essex countryside.
To mark 200 years since the House of Commons Library appointed its first Librarian, and the first ever 'National Democracy Week', the Library is open for tours on Saturday 7 July.
This is almost certainly not a complete list of all the outdoor film screenings taking place in London this summer, but it's probably not far off.
For a few days this summer, the restored gardens of Spencer House in central London will be open to the public.
A nearly 150 year old church in South London is opening its tower for one day to let the public climb up and see the views from the top.
If you want to attend the memorial service being held in Westminster Abbey next month to celebrate the life of Professor Stephen Hawking, then a public ballot opens today.
Three days of trees in May. A festival to celebrate that great shade creator, pollution cleaner, pleasure giver, the urban tree.
Gin, Umbrella Jousting, Gin, Three-Trousered Limbo, Gin, Moustache Wrestling, Gin, Quill Throwing, Gin and Bounders.