Decks of cards or paper/whiteboards
This one is best for individuals
This can be anywhere
This one requires some prep work, before the planned evening of silliness you will need to send out a list of questions to everyone that have a numerical answer. For the game give everyone a run of cards equal to the number of players (e.g., if there are 6 players everyone gets Ace - 6). Then you will run through the questions you asked everyone and remembering their response they will have to guess where they ranked with in the group. For example, if you asked the group of 6 how many rolls of toilet paper they have in their house, they would then hold up Ace if they think they have the most, 6 if they think they have the least, or anywhere in between. Points awarded for correct guesses, if there are identical responses you can let them know in advance there is one less option this round.
Some examples of questions I have used:
Eggs in the fridge
Mugs in the house
Number of steps inside and out
Number of cars to drive past your house in 5 minute window
How many first cousins you have
App icons on your phone homescreens
Number of steps from the end of your bed to the kitchen table
Ages of everyone in your house added together and divided by the number of feet in your house (including pets)
Scoring is, as always, completely arbitrary, you can award as many points as you like for correct answers. Decide how you wish based on the number of players.
If it is a large group you can use paper (or whiteboards!) instead of cards and they write their answers.
You don't have to stick to rankings, you can switch from cards and ask them to guess who cam first/last, what the average was, etc. I have even asked them for the first letter and number to appear in their license plate and then on the night asked them to write a word that starts with the letters and has as many letters as the number. You get the idea.
You can ask these questions the same day or weeks in advance so they have forgotten you ever asked them.