- the button Sawyer pushed to get the Apollo candy bar out of the vending machine. (Ep: 6x17, The End)
- the table Charlotte and Miles were sitting at during the concert in the flash-sideways. (Ep: 6x17, The End)
- the extension housekeeping is to call in Anthony Cooper's retirement home. (Ep: 6x14, The Candidate)
- the beginning of David's mom's address. (Ep: 6x5, Lighthouse)
- Jack's assignment on the cave wall. (Ep: 6x4, The Substitute)
- the last two digits of the license plate of the pickup that young Kate and Tom stood by when they decided Kate would steal from the store. (Ep: 5x16, The Incident)
- years on the front of the Sports Illustrated Miles looks at. It says, "After 23 Years New Boss in L.A." (Ep: 5x13, Some Like it Hoth)
- what Charles says to dial if Locke needs to get ahold of him (two, three). (Ep: 5x7, The Life and Death of Jeremy Bentham)
- the slip at the marina where Ben told Jack to meet him. (Ep: 5x4, The Little Prince)
- one of the kids' jersey's at Hurley's birthday party. (Ep: 4x12, There's No Place Like Home Part 1)
- the taxi cab license plate: 2369. (Ep: 4x7, Ji Yeon)
- seconds on the clock Daniel takes from the rocket. (Ep: 4x3, The Economist)
- part of the code to activate the security fence (1623). (Ep: 3x15, Left Behind)
- the room where Karl was kept. (Ep: 3x7, Not in Portland)
- the storage unit where the money is kept. (Ep: 3x4, Every Man For Himself)
- clips that flipped by in Eko's dream. (Ep: 2x21, ?)
- one of the cop cars parked in the police station parking lot. (Ep: 2x20, Two for the Road)
- years Isaac had been healing. (Ep: 2x19, S.O.S.)
- people on the deck that was meant to hold eight. When Hurley walked on it, it collapsed, killing two people.(Ep: 2x18, Dave)
- Dave tells Hurley about Leonard, "What's he going to do, call you a 23?" (Ep: 2x18, Dave)
- the total of the numbers of Henry Gale's zip code when added together: 55391. (Ep: 2x17, Lockdown)
- years in age that Sayid was when the Americans came to his country. (Ep: 2x14, One of Them)
- the episode title in "The 23rd Psalm". (Ep: 2x10, The 23rd Psalm)
- Locke's stumble when he quickly enters the code into the computer. (Ep: 2x9, What Kate Did)
- the timer setting in seconds when Jack and Locke return to find Kate has left the hatch after she thought Sawyer was Wayne. (Ep: 2x9, What Kate Did)
- days after the crash that Goodwin killed Nathan. (Ep: 2x7, The Other 48 Days)
- survivors of the tail section crash. (Ep: 2x4, Everybody Hates Hugo)
- one of the numbers on the countdown clock when it resets. (Ep: 2x2, Adrift)
- the day that the Apollo candy bar expires. (Ep: 2x2, Adrift)
- the spin dial lock setting. (Ep: 2x1, Man of Science, Man of Faith)
- Hurley and Kate's discussion topic. (Ep: 1x24, Exodus Part 2)
- the gate that passengers entered to board Flight 815 in Australia. (Ep: 1x24, Exodus Part 2)
- minutes past 5 a.m. that Walt wakes up Michael in the hotel. Episode 1x24, Exodus Part 2
- Hurley looks up at a sign in the airport that says gates 14 thru 23. (Ep: 1x24, Exodus Part 2)
- the floor where Hurley stayed in the hotel. (Ep: 1x24, Exodus Part 2)
- the hotel room that Hurley stayed in (2342). (Ep: 1x24, Exodus Part 2)
- minutes past 5:00 when Michael looked at the clock in the hotel room. (Ep: 1x24, Exodus Part 2)
- the seat that Jack sat in. (Ep: 1x23, Exodus Part 1)
- white keys on the piano magnet in Tom's house. (Ep: 1x22, Born to Run)
- The game Mousetrap that Locke set up had the number 23 on it. (Ep: 1x19, Deus Ex Machina)
- one of the digits that appeared on the license plate of the car that hit Locke. (Ep: 1x19, Deus Ex Machina)
- the street that Michael told Walt that the Flatiron building was on in New York. (Ep: 1x17, In Translation)
- the minute hand on the watch on Sun's father's wrist when he signed the document. (Ep: 1x17, In Translation)
- the minute hand on the watch on Jack's wrist when he signed the papers his father had given him. (Ep: 1x11, All the Best Cowboys Have Daddy Issues)
- times Jack hit Charlie's chest to try and revive him. He finally stopped, then started again and Charlie began to breathe. (Ep: 1x11, All the Best Cowboys Have Daddy Issues)
- gallons of water a day that Jack estimated that 46 people were drinking. (Ep: 1x6, House of the Rising Sun)
- the minute hand when Michael gave Jin the watch back. (Ep: 1x6, House of the Rising Sun)
- the seat that Howard was in. Claire mentioned Howard and his seat, number 23C, in the ceremony for those who died. (Ep: 1x4, Walkabout)
- dollars times 1000 that Kate asks the Marshal if Ray ever got. (Ep: 1x3, Tabula Rasa)
ADDITIONAL SOURCES:
TV Dramas About.com
Teen TV/Movies About.com
4815162342.com
The Lost Numbers
Lost Hatch
Finding Lost: The Unofficial Guide.