Expedia have a coupon code valid for $ 20 off most activities (or "things to do") when applied at checkout with a minimum spend of $ 60. Code can only be used once per account. Base on the history of this discount, it excludes popular attractions like Disney or Universal.

Expedia [expedia.com]
Promotional Code: JAN20US
Valid thru January 26, 2019 11:59pm PT.
Travel Period: thru August 31, 2020
Minimum spend: $ 60 USD