Custom Heroes is one of our favourite games to start a gaming night (it plays up to 6, you can explain it very quickly and plays under an hour).
Custom Heroes is a card-crafting, climbing trick game in which plastic cards are added to sleeves in order to modify the cards already in those sleeves.
The players attempt to win rounds by getting rid of their cards as quickly as possible using the classic climbing trick mechanic. e.g. If a player leads with three 4s then the next player must play three of a kind of equal or higher value. When all players pass, the last player to have played cards leads a new trick with whatever card or set of equal cards they want. Go out of cards first for first place, second for second, etc.
However, you also have advancements you can sleeve onto your cards. These may increase or decrease the value of the cards, or even add new abilities such as turning a card into a wild or reversing the direction of the values (i.e. you are now playing lower numbers instead of higher) or making cards count as multiple copies of themselves, etc.
If you would like to see how it plays, watch the BGG show GameNight!: