Sendai Umino-Mori Aquarium has a variety of attractions, such as a large aquarium that recreates the abundance of marine life in the Sanriku Ocean, nearly 100 water tanks of exotic fish and animals from all over the world. It boasts the largest dolphin and sea lion performances in the Tohoku area, and encounters with marine animals including penguins and sea lions.
https://discoversendai.travel/places/sendai-umino-mori-aquarium/

Enjoy shopping and dining at Mitsui Outlet Park Sendai Port, located near the aquarium. There are restaurants and a food court where you can enjoy meals and desserts unique to Sendai.
https://discoversendai.travel/places/mitsui-outlet-park-sendai-port/

Visitors can view the Sasa-kamaboko fish cake production process; white fish ground to a paste and baked in the shape of sasa (bamboo) leaves and visitors can take advantage of the facilities provided, to try them hot off the grill! At the Tanabata Museum, you can see the Sendai Tanabata decorations – for the festival which is held for 3 days in August – all year round, and you can also experience making miniature Tanabata decorations.
https://discoversendai.travel/places/kanezaki-sasakama-kan/

How about enjoying a beef tongue dinner around Sendai Station or Kokubuncho area?

Grilled beef tongue originated in Sendai. The first restaurant specializing in grilled beef tongue opened in 1948. Now grilled beef tongue is well-known as the city’s most famous cuisine. In fact, there are over one hundred beef tongue restaurants in Sendai.
https://discoversendai.travel/itineraries/three-beef-tongue-restaurants-to-try-in-sendai/

SENDAI Pageant of Starlight (running from early to late December)

Jozenji-dori Avenue becomes a tunnel of light every December as the New Year approaches. The trees along the avenue and its central promenade are decorated with lights in a striking illumination display.

The Pageant of Starlight has been held in Sendai since 1986, and has become a mainstay of the event calendar. The decorations have grown in scale over the years, and today use nearly 450,000 LED lights.
https://discoversendai.travel/places/sendai-pageant-of-starlight/

This is an interactive participatory museum where children can enjoy the wonderful world of Anpanman, as well as a shopping mall full of goods featuring the original Anpanman characters and it also offers other unique services. An entertaining live show with Anpanman and his friends is held once each day.
https://discoversendai.travel/places/sendai-anpanman-childrens-museum-mall/

Sendai Station has a wide selection of Japanese cuisine, including sushi and beef tongue, as well as Italian, Chinese, and other international cuisines.

Sendai PARCO has the Tohoku region’s finest collection of entertainment boutiques, where you can enjoy shopping at popular character shops such as the Pokémon Center Tohoku.
https://discoversendai.travel/places/sendai-parco/

“Sendai Castle,” also known as Aoba Castle, was built on Mount Aoba by Lord DATE Masamune and serves as a popular tourist spot that conveys the history of Sendai and the intentions of Masamune. The original stone walls from the castle’s construction still remain, allowing visitors to get a sense of the long-lasting over 400 year history of the city and the high level of architectural skills from that time. 
https://discoversendai.travel/places/site-of-sendai-castle/

How about having beef tongue dinner around Sendai Station or Kokubuncho area?

Sendai beef is rated A-5 or B-5 by the Japan Meat Grading Association. This rating denotes that Sendai beef is of the highest grade.
https://discoversendai.travel/eat/sendai-beef/

Enjoy winter sports at the ski resort at Spring Valley Sendai Izumi Ski Resort, on the outskirts of Sendai City! On weekends and holidays, you can enjoy sledding and other activities at Snow Adventure Kingdom, a fun spot for kids to play in the snow!
https://discoversendai.travel/places/ski-resorts/

How about some unique Sendai zunda sweets or Sendai versions of famous characters?