From the Comprehensive Rules 4.0:
The word spot sets up a requirement for playing a card or using a special ability in conjunction with a noun such as, “To play, spot an Elf.” This is equivalent to, “An Elf must be in play and active for you to play this card.”
Cards in your dead pile are active during your turn, but they’re not in play. You can’t spot a card in your dead pile.
Normally, you don’t have to spot all the cards in play that meet the requirement if you don’t want to.
If a card says, “for each Elf you spot” and there are 2 Elves in play (and active), you may choose to spot 2 Elves, 1 lf, or none.
However, if a card says, “you can spot,” that means you don’t have a choice and you have to spot anything and everything that meets the requirement.
“While you can spot The Balrog, kip the archery phase” means you can’t make a choice (it either works or it doesn’t).
To spot a “Free Peoples culture” means to spot any Free Peoples card of that culture. You cannot spot a Gollum culture Shadow card to spot a Free Peoples culture. Events are not in play and can never be spotted.