Hi Kelsy, welcome to the forum.
For starters I'd recommend hiring a car to explore the area.
Here are some ideas for things to do as listed in our magazine guide:
1. Visit the local museum (Map H9)
2. Evening walk and feed the fish at Nong Prajak Park (Map I7)
3. Dinner at a lakeside restaurant (Map I6)
4. Shopping at the night markets (Map P12)
5. Visit City Shrine, take photos at dusk. (Map K9)
6. Shopping at the city Mall (Map O11)
7. Enjoy a relaxing massage (Map J8, O12, 013)
8. Sample the food at the local night market ( P12)
9. Listen to live music at UD Bazaar (Map Q12)
10. Play a game of tennis, swim or work out at BB Fitness Club (Map G1)
11. Take a short Thai language course with Ajarn Shuan Tel. 085-683-3125
13. Visit a local produce market (Map L6)
14. Buy some silk from Naa Kha Silk Weaving Village (Page 55 Map D4)
15. Visit the beautiful Phu Phra Bat Historical Park (Page 55 Map C3)
16. Explore Suwannakhu Cave (Page 55 Map C3)
17. Enjoy the waterfall at Nam Tok Yung Forest Park (Page 55 Map B3)
18. Visit Ban Chiang Museum & heritage site. There is also a winery close by for wine tasting (Page 55 E4)
19. Enjoy a day out or camp overnight at Phu Foilom Park. The waterfall looks best this time of the year. (Page 55 Map D5)
20. Visit Kham Chanot forest temple (Page 55 Map E3)
21. Watch a live band play on top of the Ton Koon 22. Hotel with nice views
over Udon Map K9.
23. Enjoy fresh water BBQ shrimps and the local delicacy ‘Somtam’ by the lake (Page 55 D4) Lot's of restaurants like this on route 2 towards Nong Khai
24. Have a day out fishing at Sabai Sabai fishing park or Nongsai fishing park
nong-sai-fishing-park-udon-thani-t12772.htmlsabai-sabai-fishing-park-udon-thani-t12975-30.html25. Play mini golf or tackle the climbing wall
sabai-sabai-fishing-park-udon-thani-t12975-30.html26. Take a day or two to visit Nong Khai for the Ta Sadet Market, temples and Sala Kaew Ku Statue Park
http://www.nongkhaimap.com27. Play ten-pin bowling 3rd floor Central Plaza
28. Watch a movie at Majorplex cinema
29. If you have young kids there are mini play parks at Nong Prajak Park, Nong Sim Park, Nong Bua Park and UD Bazaar.