Instead of spending all your green this Black Friday, why not surround yourself with greenery this year?On November 24, the National Park Service and 16 state park associations are hosting special events and offering free admission as their own Black Friday "deals" to encourage people to head outdoors and enjoy nature.According to Travel + Leisure, state parks in Arizona, Colorado, Indiana, Kansas, Michigan, Minnesota, New Mexico, New York, Vermont and Washington are offering free admission this Friday, while those in Alaska and Oregon will have free parking.There are free events and contests on Friday happening in Arkansas, Tennessee and Virginia, while some California locations are offering a limited number of free admission passes. If you're looking to get away for longer, state parks in South Carolina are offering discounts on campsites and cabins.While the National Park Service won't be waiving entrance fees on Black Friday, many parks will be hosting special events and offering free guided hikes and classes. See the full list of what parks are offering here.For more outdoor inspiration, REI launched a new visual search engine that pulls images from over 6 million posts on Instagram's #OptOutside hashtag to help people find the best locations near them for the company's third annual #OptOutside campaign, which also includes closing all 151 of their stores on Black Friday and giving their employees a paid day off.