As DMK chief M Karunanidhi turns 94 today, his birthday party will serve as a gathering for more than one cause. While his party will mark the occasion as one to celebrate his sixty years of being a legislator without losing a single election, a host opposition parties will huddle around in what is being seen as a show of unity ahead of the Presidential election. Among the expected attendees are Congress vice president Rahul Gandhi, Bihar Chief Minister Nitish Kumar, National Conference leader Omar Abdullah, Sitaram Yechury of the Left, Sharad Pawar of the Nationalist Congress Party. The BJP has not been invited.