Nob Nation is the title of a series of topical comedy pieces broadcast Monday to Saturday every week on Ireland's two biggest radio stations, RTE 2FM and RTE Radio One since November 2006. There are more than 70 characters used in the comedy sketches which are based on people from Irish and international public life involved in politics, sport and entertainment. All character acting and singing is done by mimic Oliver Callan.

The sketches are first broadcast in the morning on The Gerry Ryan Show on 2FM which has more than 315,000 listeners daily and is ranked number one in the national radio listenership category of 20-44 year olds. Nob Nation is then repeated in the afternoon on Mooney on RTE Radio One, a show which has a growing audience of 150,000 listeners and again at night on The Frequency on 2FM. The best comedy sketch of the week is featured on Playback on Radio One on Saturday mornings and on The Saturday Show on 2FM on Saturday afternoons.

Nob Nation is also frequently at the top of Ireland's official weekly itunes podcasting charts.

The title of the comedy sketches is based on the intimation that the characters sent-up in the sketch are 'Nobs' or 'eejits', or that Ireland is a nation of 'eejits'. However, it also has a naughty side since presenter Gerry Ryan adopted the catchphrase 'Get your nobs out for Ireland' when introducing the pieces.

Bertie Ahern, Ireland's Taoiseach or Prime Minister, is the main star of Nob Nation, alongside his chief rival Enda Kenny, the leader of opposition party Fine Gael. Bertie is portrayed as a rough, mischievous figure who plays on his huge personal popularity and his certainty to win at any challenge. He invariably teases, insults and laughs at Kenny. Kenny for his part is portrayed as a weak and unpopular figure who answers back the Taoiseach and is obsessed with his image and drinks 'tins of Lilt'. The Dáil is portrayed in the series as a loud and boisterous classroom where the TDs attack and jeer each other, creating mayhem and discussing everything from cartoons to quizzes instead of issues of national importance.

The two figures are central to Nob Nation's portrayal of the General Election 2007. Senator David Norris, a gay rights campaigner in Ireland, is also a very popular star of the sketches and is portrayed as a gay superhero, claiming that 'gay is the way'. In the past he has been fixated with Liverpool footballer Steven Gerrard and Cork All-Star hurler Seán Óg Ó'Hailpín. Senator Norris is said to enjoy the sketches enormously and even phoned in to the Mooney Show and went live on the air to testify to his affection for it.

Nob Nation has also been notable for its satirical take on RTE itself, even lampooning the 'Mooney Goes Wild' programme, presented by Derek Mooney, which broadcasts the sketches. RTE's Liveline programme is also a regular feature of the comedy series, in which presenter Joe Duffy is besieged by many of the sketches' stars discussing the main issues of the moment. Pat Kenny, Dave Fanning, Marian Finucane, Gay Byrne and Gerry Ryan himself are also among the 'victims' of the series.

The sketches have caused controversy inside and outside RTE since its inception. In January 2007, a number of Sunday newspapers reported that popular presenters Dave Fanning and Derek Mooney had fallen out over who would get to broadcast the series on Radio One. Both men later denied the argument had arisen. Then, in the same month, one sketch was axed by RTE statioin bosses because it contained the word 'willy', a move which prompted much mirth and derision in the national press. In February, listeners to Mooney phoned the show to complain after it appeared that stand-in presenter Aonghus MacAnally appeared to angrily cut-off Sinn Fein President Gerry Adams. However, MacAnally had to apologise to angry callers, revealing that 'Mr Adams' was in fact mimic Oliver Callan.

Callan is from Co Monaghan and is habitually referred to in the press as 'The Monaghan Mimic', a phrase coined by The Sunday World newspaper.

In January 2007, he was named by Village Magazine as one of its 'People of the Year 2007', a list which included Gordon Brown and Enda Kenny. The magazine wrote of Callan:

"It’s been a heady few months, which culminated in the Gingerman pub in Dublin recently when Callan got to put his pitch-perfect Enda Kenny impersonation to the ultimate test – the man himself. Kenny was gracious, but preferred Callan’s Bertie Ahern. Which is appropriate, because a couple of weeks previously, Callan had been in Fagan’s in Drumcondra and got to do his Bertie Ahern for Bertie Ahern. Bertie and his mates enjoyed it – but they preferred his Enda."