In the morning, head to Solang Valley for skiing or snowboarding. After lunch, go for paragliding or zorbing. In the evening, enjoy a bonfire with music and dance with your friends.
Start your day with a visit to Hidimba Devi Temple. Then, explore the streets of Old Manali, which are filled with cafes, bars, and shops. In the afternoon, go for river rafting in the Beas River. In the evening, enjoy the vibrant nightlife of Old Manali.
Visit the Naggar Castle, which is a beautiful amalgamation of European and Himalayan architecture. Explore the castle and its museum, and then head to the Nicholas Roerich Art Gallery, which features paintings by the famous Russian artist. In the evening, relax at the hot springs in Vashisht.
Visit the Manikaran Sahib Gurudwara, which is a holy site for Sikhs and Hindus. Take a dip in the hot springs, which are believed to have healing properties. On your way back to Manali, stop at the Kullu Shawl Factory to buy souvenirs. In the evening, enjoy a farewell dinner with your friends.
You can also consider visiting the Rohtang Pass for snow activities, but it might be closed in December due to heavy snowfall. You can also take a day trip to Kasol, which is a beautiful village with scenic views. To maximize your fun, hire a party bus for transportation and visit the local clubs and pubs in Manali. Don't forget to try the local cuisine, especially the Himachali Thali. Have a safe and memorable trip!