Five stories that have North Texas talking: A holiday song with a North Texas connection goes viral, the federal government has determined that Dallas’ affordable-housing practices are violating civil rights laws, a Dallas dentist wants to be your senator, and more.

• The Perot Museum of Nature and Science is offering a high-tech twist on its popular exhibits. Starting this week, visitors can check out tablets that offer content in English and Spanish that enhance their museum tours – the tablets virtually simulate a hurricane or earthquake, feed a dinosaur and teach about parts of the body. Samsung donated more than 500 tablets and helped design, program and implement the virtual features. Content has been created for the Human Body exhibit in the Being Human Hall on Level 2, the Extreme Earth exhibit in The Rees-Jones Foundation Dynamic Earth Hall on Level 3, and the Alamosaurus fossil in the T. Boone Pickens Life Then and Now Hall on Level 4. On Sunday, the museum marked its first birthday.

• The George W. Bush Presidential Library and Museum set a single-day attendance record Friday, attracting about 3,800 visitors. That’s thanks in part to a new holiday exhibit that showcases the Bushes 2001 White House celebration, The Dallas Morning News reports. The library and museum typically see about 1,000 guests each day. More than 270,000 have visited since the complex opened to the public in May, The News reported.

• Pentatonix, the a capella group with Arlington roots, has produced a holiday video that’s gone viral. The group performs “Drummer Boy,” which has been viewed more than 8 million times on YouTube. NPR’s Morning Edition explored the group on a recent program. “Pentatonix is a five-person singing group that formed to compete in the NBC a cappella competition show ‘The Sing-Off.’ Three of its members were friends from high school, but the full group met for the first time just hours before the show to rehearse. Pentatonix ended up winning the competition.” Here’s the video.

• Dallas’ affordable-housing practices are violating civil rights laws, a U.S. Department of Housing and Urban Development investigation has found. The department has determined that the housing practices promote discrimination against minorities and the disabled, The Dallas Morning News reports. “The evidence shows that there was a pattern of negative reactions to projects that would provide affordable housing in the northern sector of Dallas,” according to a 29-page letter outlining the findings. “Those decisions were inconsistent with the goals required by HUD program obligations.” City Council member Scott Griggs, vice chairman of the council housing committee, told The News that the HUD letter confirms the long-standing image of Dallas as a city divided between a northern sector for better-off people who can pay market-rate rents and a southern sector for low-income people who need rent subsidies.

• Add a North Texas name to the growing list of U.S. Sen. John Cornyn‘s opponents in 2014. Dallas dentist David Alameel, a Democrat, told the Texas Tribune he will run for the seat, joining at least six other hopefuls from both major parties. In the Democratic primary, Alameel faces El Paso lawyer Maxey Scherr and former GOP House candidate Michael Fjetland of Houston, who switched parties. Cornyn’s challengers in the Republican primary are relative unknowns, the Tribune reports. They include attorney and activist Linda Vega, Liberty businessman Dwayne Stovall and Tea Party candidates Reid Reasor and Chris Mapp.