Colorado still has a handful of quirky, outdated, or oddly specific laws on the books—often remnants of “blue laws” (Sunday restrictions from historical religious or rest-day norms) or local ordinances addressing long-ago concerns. Most are rarely (if ever) enforced today due to changing times, but they technically remain valid unless repealed. Recent checks (as of 2025–2026) confirm many persist in statutes and municipal codes, with no widespread repeals of these classics. Enforcement is spotty at best—some have seen rare citations, others are more trivia than threat.

enjuris.com Here’s an updated rundown of the most commonly cited “hidden” or unused ones, drawn from current legal summaries and ordinances:

Statewide Laws

• No selling motor vehicles on Sundays: Car dealers (new, used, or secondhand) cannot sell, barter, or even display cars for sale on Sunday. Tires, accessories, boats, snowmobiles, and parts are fine. This is a classic blue law (C.R.S. § 12-6-302 / formerly § 44-20-302). It was renewed as recently as 2017 and remains in effect—no repeal efforts have succeeded. Dealerships largely accept it for family/rest reasons. grunge.com
• Intoxicated riding of animals (like horses) on highways: Horses and other animals count as “vehicles” in this context, so riding one while drunk can lead to a DUI-style charge (C.R.S. § 42-4-805(4)). It has been enforced (e.g., a Colorado Springs case involving a man on a horse). enjuris.com
• Mutilating or damaging rocks in state parks: You can’t break, remove, or alter natural rock formations. This protects parks but is rarely cited unless damage is obvious. sargonlawgroup.com

City- and Town-Specific Oddities

• Aspen: Throwing snowballs (or any “missiles”/projectiles) in public is banned, along with catapults or similar devices aimed at people, buildings, or property (Aspen Code § 15.04.210). It’s meant to prevent injury or damage but is almost never enforced for casual play. enjuris.com
• Pueblo: Property owners must keep dandelions and certain weeds trimmed under 10 inches (Pueblo Code § 7-4-2). This is more of an active nuisance ordinance than a truly “hidden” one and can be enforced for aesthetics, fire risk, or pests. enjuris.com
• Boulder:
  • No rolling, throwing, or moving boulders onto public property (Boulder Code § 5-4-8).
  • You can legally insult, taunt, or challenge a police officer—until they tell you to stop (Boulder Code § 5-3-6; a narrow “fighting words” rule—not recommended to test).
  • Outdoor upholstered furniture (not made for outdoors) is restricted on porches for fire/sanitation reasons. enjuris.com
• Alamosa: It’s illegal to “project a missile” at any vehicle (broadly includes throwing anything by hand or device; Alamosa Code § 11-50). enjuris.com
• Vail: Skiing or snowboarding while intoxicated is prohibited (Vail Town Code § 6-3H-9). Very “Colorado” and tied to ski safety rules. enjuris.com
• Sterling (Logan County area): Dyeing pets is banned (Sterling Code § 4-9). An old rule that sees almost no enforcement. enjuris.com
• Logan County: Kissing a sleeping woman is technically illegal (an archaic, culturally dated ordinance that is never enforced). sargonlawgroup.com

Common Myths (Not Actually on the Books or Repealed)

• Denver “no lending your vacuum cleaner to a neighbor,” “no driving black cars on Sundays,” or similar— these are urban legends with thin or no documentation in current codes. sargonlawgroup.com

These laws often linger due to legislative inertia (repealing every quirky local rule takes effort). Some, like the Sunday car ban or drunk horseback riding, have real-world roots in safety or tradition and occasionally surface. Others (snowballs, boulders, pet dyeing) are essentially dormant. For the absolute latest status, check official sources like Municode, Colorado Revised Statutes, or consult a local attorney—municipal codes can update quietly. They make great trivia, but testing them isn’t worth the risk of a surprise ticket!